The causus belli was twofold, and was aimed at the Russian people:
1. Prevention of NATO encroachment toward Russia
2. Protection of ethnic Russians in Donbas
Any and/or all of the following would have weakened or broken Putin's narrative:
1. Stop the military buildup in Donbas that had started in 2021
2. Cease admission of new NATO member states for 3-5 years
3. Stop the process of Ukraine getting closer to NATO and the EU
4. Reduce or stop US military assistance funding to Ukraine
5. Drop the Biden administration's economic sanctions of Russia
6. Continue implementation of the Minsk accords
7. Stop the planned deployments of US missiles to Ukraine
There are many more options. The US administration in 2020 was bringing Ukraine into the fold (because it wanted to be there), but that is not a recipe for peace. NATO had previously agreed not to get close to Ukraine or other states bordering Russia.
The basic flaw in what you're suggesting (that the war could have been averted by mollifying Putin on the terms of his stated narrative), is that, as we both seem to agree, the stated narrative was never the real basis for his decision to invade.
Putin's actual reasons, in turn, seem to have been primarily about:
1. Securing the 3 currently (as of Feb 2022) occupied regions, especially the Crimea, for permanent annexation. Russia's position in the Crimea in particular was at the time severely compromised, due to Ukraine's shutting off of its water access. It also "needed" a land bridge (around the Azov) in order to be reasonably secure in the long term. (We put "needed" in quotes here to remind ourselves that this was the regime's internal desire, not any kind of objective or real "need"). As gravy, or as a way of offsetting the cost for the whole operation, there was also the matter of the Donbas region's significant lithium reserves (estimated at $3T).
2. Permanent deterrence of any NATO bid on Ukraine's part, likely involving some form of formal declaration of permanent neutrality (Finlandization).
3. As gravy, anything it could have also won in terms of regime change in Kyiv, preventing whatever rump state (if any) that remained in Western Ukraine from joining the EU, or simply damaging its chances for success and prosperity generally ("wrecking it", in Mearsheimer's words) would have been a very signicant plus.
The thing is, (2) by itself could have been had without resorting to a full-scale invasion. The West was eager for some kind of deal to end the 2014-2022 conflict, and having Ukraine in NATO was always optional, as far as it was concerned.
But the price for Putin -- forgoing his paramount desire for (1) -- would have been far too high. Plus he thinks of himself as a visionary leader, destined to make his mark on history, and for many years had deluded himself as to Russia's actual capabilities for military adventures of this sort.
So that's why he went "whole hog" in Feb of 2022. The main point here is that there doesn't seem to be much logic in thinking the war could have been avoided by addressing the stated narrative. When Putin's real reasons for invading, with emphasis on (1) above, would be in no way addressed by tactical appeasement of this sort.
You would greatly benefit from watching https://www.youtube.com/playlist?list=PLcfqP0PtWDcGKIHGTTbVl...