hi bro, a friend of mine changed his X battery once. another friend changed his iPhone 12 Pro battery once and still using it. the X user sold it recently as he needed to change the battery again and yes 2 years approximate time was again he got for his normal usage.
for battery I always prefer authorised service center. for other spares we may check with third party options. but for battery its risky if you are planning to continue using the device.
If you are planning to upgrade then its not worth changing the battery. else you can change battery and continue using it. if next year any apps support stopped like payment or banking apps by govt, then you may have to upgrade. by that time you will have decent battery health too.