tomcrownshawYea somehow i fixed it too (i hope) in this way , giving the 30 watt charge (i often use the ultra stable mode).
I have had numerous issues with my Zenfone 8 battery. First was literally after unboxing it drained ridiculously fast. In October the problem recurred. Both times I fixed it with a 100% cycle charge. Generic battery drainer app is useful.
I didn't check the stats as to what was draining it in October as I had already done this fix and knew it worked. I've no idea why it seems to work other than perhaps it recalibrated some part of the BMS.
I can now get two days out of it with conservative use. Hope this helps.