The charge control limiting was removed from Lineage for Pixel devices a few months back. The issue report I found at the time indicated it wasn’t working right so they removed it. Anyway, this user reports a workaround solution:
Regarding the update which essentially just reports the battery capacity as less than it actually is (that is what I understood about the 4a and 6a “Google updates”), most users I see are looking for ways to not have those updates forced on them :-). I am not certain but I think those updates are not included in Lineage (and thus iodéOS) builds.
Regarding your 6a getting quite warm, wondering if there was an out of control process?