May Hashem grant you a year of great joy and success in Ruchnius and Gashmius
בינך להקדוש ברוך הוא, בינך לחברך, ובינך לעצמך
and a quick dvar halacha:
The Maharil says that one should not begin Yomtov earlier than necessary on the first night of Rosh Hashanna, and should, therefore, only make kiddush after Tzeis. Because Rosh Hashanna is a day of judgment, it is inappropriate- even counter productive- to offer one's self for judgment before being summoned. It expresses audacity and overconfidence, or indifference. In any case, it is unwise to begin Rosh Hashanna before necessary. He specifies Kiddush, suggesting that kiddush is a more serious matter than davening, because kiddush is deoraysa.
Reb Moshe, in an early teshuva (OC I 170, page 292), written in Lyuban, paskens that if, on the first night of Rosh Hashanna, one davenned the correct shmoneh esrei for Rosh Hashanna, but said האל הקדוש instead of המלך הקדוש, he does not have to repeat shmoneh esrei.
This was first proposed by a Yesh Omrim in the Talmidei Rabbeinu Yona in Brachos, but rejected. It next appears in the Chayei Adam, who brings this from the gaon Rabbi Avraham Abbale Pasveller (b. Pasval, 1764, d. Vilna, 1836, for a time contemporary with the Vilner Gaon, who lived from 1720 to 1797,) head of the Beis Din of Vilna. The Mishna Berura rejects this opinion, and even the Chayei Adam calls it "a big chiddush."
Reb Moshe is surprised that the Gaon Reb Abbeli didn't mention the Talmidei Rabbeinu Yona's earlier rejection of this shitta. So Reb Moshe says that the Talmidei R"Y are talking about someone who says the entire weekday Shmoneh Esrei. Reb Abbeli is talking about someone who davenned the correct Rosh Hashanna shmoneh esrei and the only error was saying Keil instead of Melech. Although there is issur melacha at night, and all the laws of yomtov apply, the judgment of Rosh Hashanna does not begin until morning. The concept that saying המלך הקדוש is essential, and that without it you haven't properly davenned shmone esrei, only pertains when Hashem is exercising Malchus through judgment, and judgment does not begin until morning. (He proves this from the Gemara that says that the Beis Din shel Maalah seats itself only when Beis Din shel Mattah is seated.)
This was first proposed by a Yesh Omrim in the Talmidei Rabbeinu Yona in Brachos, but rejected. It next appears in the Chayei Adam, who brings this from the gaon Rabbi Avraham Abbale Pasveller (b. Pasval, 1764, d. Vilna, 1836, for a time contemporary with the Vilner Gaon, who lived from 1720 to 1797,) head of the Beis Din of Vilna. The Mishna Berura rejects this opinion, and even the Chayei Adam calls it "a big chiddush."
Reb Moshe is surprised that the Gaon Reb Abbeli didn't mention the Talmidei Rabbeinu Yona's earlier rejection of this shitta. So Reb Moshe says that the Talmidei R"Y are talking about someone who says the entire weekday Shmoneh Esrei. Reb Abbeli is talking about someone who davenned the correct Rosh Hashanna shmoneh esrei and the only error was saying Keil instead of Melech. Although there is issur melacha at night, and all the laws of yomtov apply, the judgment of Rosh Hashanna does not begin until morning. The concept that saying המלך הקדוש is essential, and that without it you haven't properly davenned shmone esrei, only pertains when Hashem is exercising Malchus through judgment, and judgment does not begin until morning. (He proves this from the Gemara that says that the Beis Din shel Maalah seats itself only when Beis Din shel Mattah is seated.)
According to this, then, the rule of the Maharil should not be create a problem with davening maariv early even if he is mekabeil Yomtov explicity. One has nothing to do with the other. You can be mekabeil yomtov as much as you want, but the din does not begin until the next morning.
As I said before, the Maharil was only talking about making kiddush early, not about davening early, and I'm assuming that this is bcause a person can daven before he is mekabeil yomtov, while Kiddush is a real kabbalas yomtov. (Only according to the Rambam can a person make kiddush without being mekabeil Yomtov, and I believe that's a daas yachid.) But the minhag is to avoid davening maariv early, too, out of concern for the Maharil and in general in order to say Krias Shma in the right time.
So at the minyan I'm making, we're davening maariv after ג' רבעי מיל out of respect for the Maharil and so Krias Shma shouldn't be too early, but we're not waiting an hour, on the basis of Reb Moshe's psak.
As I said before, the Maharil was only talking about making kiddush early, not about davening early, and I'm assuming that this is bcause a person can daven before he is mekabeil yomtov, while Kiddush is a real kabbalas yomtov. (Only according to the Rambam can a person make kiddush without being mekabeil Yomtov, and I believe that's a daas yachid.) But the minhag is to avoid davening maariv early, too, out of concern for the Maharil and in general in order to say Krias Shma in the right time.
So at the minyan I'm making, we're davening maariv after ג' רבעי מיל out of respect for the Maharil and so Krias Shma shouldn't be too early, but we're not waiting an hour, on the basis of Reb Moshe's psak.
Here's a compilation of shittos regarding the Maharil, taken from ישראל וזמנים by
כתוב בשו׳׳ת מהרי׳׳ל (סי׳ ל״ג, ד״ה ועוד) דיש שאין מוסיפין מחול על הקודש בר״ה משום דיומא דדינא הוא, ועל כן אין
מקדשין אלא בלילה ממש שלא להקדים יום הדין עיי״ש [ומבואר שם דאילו בתפלה מיהו מקדימין (רק בקידוש מאחרינן) דהעיקר הוא קידוש שעל הכוס שהוא מדאורייתא], וכ״ה בלקט יושר (עמוד פ״ו) שכן המנהג בניושטאט, מיהו המג״א (סי׳
תקפ׳׳א סק״י) מביא משם הלבוש דגם בר״ה צריך להוסיף מחול על הקודש (ומבואר בלבוש שהמתענים בער״ה אין משלימים התענית עד הלילה כדי להוסיף מחול על הקודש), ועשו״ת שואל ומשיב (מהדו״ד ח״ד סי׳ קכ״ה) שהאריך בזה, וכן המהרש״ק בס׳ שנות חיים (סי׳ ס״א) כ׳ דגם בר״ה יש להוסיף כמו בשאר יו״ט (וע״ע בספרו ס׳ החיים סי׳ חקפ״ב), ובשו״ת מנחת אברהם (סי׳ מ״ח) כ׳ במונח המהרי״ל שאין מוסיפים יותר משיעור תוספות המחוייב, אבל תוספות משהו מוסיפין, [אלא שהמהרי״ל שם נתקשה על מנהג איחור הסעודה דהא כבר קדשוהו בתפלה, וחי׳ דשמא קידוש על הכוס עיקר דהוא דאורייתא עיי״ש,
שוב מצאתי ככל דבריו הנ״ל בשרית הרמ"ה הנדפסה בשו״ת הרשב״א סוף ח״ב, אלא דעדיין צ״ע דהא קידוש על הכוס לרוב הפוסקים אינו אלא דרבנן ובשו״ת מנחת אברהם הנ״ל הוכיח מדברי המהרי״ל דקידוש ביו״ט הוא מה״ת, וס״ל להמהרי״ל דלא חל עליו תוספות שבת ויו״ט בדיבור בעלמא אלא בדברים של קדושת היום דאלח״ה סוכ״ס הלא כבר קיבל עליו חוס׳ ר״ה בחפלה, ועדיין צ׳׳ע דהא בסי׳ רס״א ובסי׳ רס״ג מבואר דתוספות שבת חל על האדם באמירח ברכו ובתפלת ערבית, ועוד דבתפלת עמידה של שבת ויו׳׳ט ור׳׳ה יש בהם דברי קדושת היום, שו״ר גם בגליוני הש׳׳ס (יומא דף פא.) שנתקשה בדברי המהרי׳׳ל