I would definitely call this a major problem. GPS on FP4 is really unreliable, see GPS fix takes very long after update (with e.g. Mapy.cz and GPSTest)
I doubt that it’s due to eSIM (more likely just a coincidence). But you are definitely not alone. Battery life after A13 update is absolutely horrendous, see FP4 battery life got worse after Android 13 update
Well, good on you. I gave up and purchased Google Pixel 8a.