There is a genuine problem of people with LFP batteries reading advice meant for NMC batteries and thinking it applies to them. I thought the same until I was put right. Charging to 100% every time you charge (on an AC charger) will not harm an LFP battery in any way you'd notice, and it is what we are told to do by MG.
MG actually took the trouble to remove from the apps of SR owners the ability to set a charge limit, so as to stop them treating the batteries as if they were NMC.
There is no way I know of to balance an SR below 100% (in contrast to the LR). You can't set a charge limit below 100%, which is what you have to do to in the LR to get it to do a partial balance at 80%. And you wouldn't want to. You have a battery you can use the whole range of the whole time, and not worry about charging it up to full and leaving it there.
Watch this video. It's really reassuring for owners of LFP and NMC batteries alike.