Is there a way to “Ignore” an Android phone’s battery percentage reading?

Dumb question, but bear with me:

I have a Sony Xperia XA1 Ultra (G3223) in my drawer, intact, except with one thing–A glaring battery problem.

About half a year ago I made the mistake of using it while charging. Problem was, the current was not enough to match up to how much power my usage was taking up. On an emergency, I dismissed it and kept using it like that for another 15 minutes. When I hastily unplugged the phone, it hadn’t charged. It stood still at 0% and turned off right there.

Since then, the battery situation was never right:

  • It would seem to hold a charge of up to 100%, but anything even remotely resembling daily usage on it resulted in it draining 1% per minute type of quickly, with no way to stop this until it inevitably plummeted to 0% even with the charger on.

  • Charging it overnight seemed to “top-up” the battery, regardless of if in standby or turned off, but the situation was always the same as above.

  • If I continue to use it on the charger, it stays on 0% but seems to eventually but very slowly go back up to 100% again, before it quickly goes back down to 0%, on the charger still.

  • Strangely, if the battery has that much charge, it still drains very quickly, but a reboot of the phone sees it start back up no problem.
    It will be stuck on 1% before it shuts down after about 15 minutes of use, only for me to turn it back on, and repeat this process over and over until it actually does die with a low battery logo warning barrier instead of the coldboot screen.

  • When on TWRP, this issue isn’t present. The phone will stay on no matter what for as long as the battery has charge. But another thing to note is that this fork of TWRP doesn’t even have a battery percentage reader. Where it should be, is just blank.
    (Yes, it’s an unofficial port for G3223. The perks of a MediaTek phone…)

I tried replacing the battery, but the same thing happens.
I tried ACC (Advanced Charging Controller) via Magisk.
I tried calibrating the battery, both the basic way and with other methods such as with a battery monitor app.

At this point, I’m convinced it’s a battery controller chip somewhere in the motherboard. But in case it isn’t:

Is there a way to make Android “ignore” this faux percentage reading similarly to how “this” TWRP does?
Is there any help for this poor XA1 Ultra’s battery situation at all?
If there’s another possible solution to this, at all, that doesn’t involve component level repair, I’ll gladly take it. If not, I’ll sell it for parts or repurpose it somehow.

Thanks in advance and sorry for the essay!

EDIT: I’m new to this place, so if my question doesn’t seem to add up or be in the right place, I apologize and will address that concern.

TL;DR: An old Xperia XA1 Ultra has an issue involving incorrect battery percentage readings that no amount of battery calibration can fix. Looking for ways to fix this, or at least circumvent or workaround it, either via some low-level kernel magic or something. Any comments or pointers appreciated! Also, I’m a newbie.