After iOS 14 - The battery health decreased from 100% to 98%

I don't quite understand what you are all up in arms about..

according to this support article

iPhone Battery and Performance - Apple Support

your battery should retain up to 80% of it's capacity after 500 charge cycles. So after 115 cycles you are worried that it fell 2%? if it's a linear relationship, it wouldn't be concerning if it had fallen 4-5% which would put your capacity at 95-96%.

If you are questioning the cycle count, 115 cycles in 9 months is only a charge cycle every ~2.3 days.

So unless I'm missing something, I would agree with them. Seems normal.

I still don't think you should be concerned about a battery being at 98%. Could just as well be coincidence that it shows the drop after updating. Or maybe there is something about the battery health calculation that was tweaked in iOS 14. I'd be more concerned if I saw the percentage dropping weekly or something that doesn't line up with the math.

Just my opinion of course