Shuva Yisrael ad Hashem Elokecha - ad v'ad b'chlal or ad v'lo ad b'chlal?

Yoma 86a according to the girsa of the Yalkut and Ain Ya’akov-

R’ Levi:tshuvah is great in that it reaches even the kisa hakavod, ad v'ad b'chlal, as the pasuk says, “Shuvah Yisrael ad Hashem Elokecha”.
R’ Yochanan: tshuvah is only ad v’lo ad b’chlal; it reaches up to, but not quite until the kisa hakavod.
Gemara: how can R’ Yochanan really hold ad v’lo ad b’chlal? R’ Yochanan himself holds tshuvah is doche a lo ta’aseh, as it is compared to a a husband remarrying a divorced woman who already remarried someone else (see gemara for pasuk quoted)? Answers gemara: R’ Yochanan holds ad v’ad bchlal with respect to a yachid, but agrees that tshuvah of the tzibur reaches even the kisa hakavod.

The entire sugya is a pliya. What does it mean to speak of ad v’ad b’chlal or ad v’lo ad when it comes to the mitzvah of tshuvah? And how does the fact that R’ Yochanan describes the geder of tshuvah as aseh doche lo ta’aseh prove ad v’ad b’chlal? Why does R’ Levi quote the pasuk of “shuvah yisrael” from Hoshea and not the earlier pasuk in parshas Nitzavim “v’shavta ad Hashem Elokecha”? And what is the difference between a yachid and tzibur?
A few weeks ago we discussed the yesod of the Shiurei Da’as (vol. 2 “Bein Yisrael laAmim”) that there are two perspectives on schar v’onesh of mitzvos and aveiros – the model of the king and the model of the doctor. When the doctor tells you to eat healthy or take medicine, if you do not listen, it is not the doctor who is punishing you by making you sick, but that is the nature of teva. However, when the king orders you to fulfill a command, e.g. pay taxes, if you fail to obey, the punishment is not a natural outcome of the behavior, but is directly imposed by the king. Mitzvos reflect an overlap of these themes.
As explained by the Sefer haIkkarim, only a willful act is punished by the Torah; once one has grown out of the mindset of cheit and done tshuvah, in retrospect, the act of sin was not willful and premeditated, but just a chance occurance. Is that opportunity to reflect on one’s will and undo a prior action a function of the model of the doctor, or a function of the model of the king? Is it implicitly part of the nature of reality, or is it a function of a special grace made possible by Hashem’s direct intercession and rachmanus? R’ Levi understood that a person can accomplish the totality of the tshuvah process through his/her own efforts – ad v’ad b’chlal. R’ Levi davka quotes the pasuk in Hoshea of “shuvah yisrael” and not the pasuk of “v’shavta” in P’ Nitzavim because the parsha in Nitzavim ends “v’shav Hashem Elokecha es shevuscha” – it reflects tshuvah which does not go all the way to accomplishing its goals but needs Hashem to reach out and help.
R’ Yochanan on the one hand tells us that man’s efforts alone leave a residue of cheit – ad v’lo ad b’chlal. On the other hand, if such a residue of cheit remained, how do we understand the analogy to a woman remarrying her husband? Drinking even a drop of poison with the best intentions can nonetheless prove fatal - tshuvah must eliminate cheit completely! The gemara’s answer distinguishing the tzibur from the individual perhaps revolves around the distinction between the model of the doctor and the model of the king. The tshuvah of the individual is of a personal nature and is not all-encompassing. It cannot catapult the world as a whole to a higher plane, and does not even completely eliminate the poison of cheit, but instead relies on the benevolence of the king to reach out to pull us up the final rungs of the ladder we climb ad v’lo ad b’chlal. However, the power of the tzibur is such that their tshuvah brings correction not just to each person’s life, but to the world as a whole – gedolah tshuvah she’mevi'ah refuah la’olam. Refuah is the role of the doctor. When the community as a whole elevates their entire environment, the complete elimnination of cheit is a natural byproduct of the tshuvah process. Shuva yisrael, this time of year when we all work together, ad Hashem Elokecha, ad v'ad b'chlal, to the highest reaches of the kisa hakavod.
(adapted from an approach based on Rav Kook’s Orot Tshuvah).