I use accubattery too but it only gives a notification, it doesn't stop charging. Would be nice to leave it charging overnight knowing that it will stop at 85%. My battery protect feature doesn't work at all (Tab S6 lite)
it hard sets the value i believe, so it will go to 100% in android but that is actually 85% of capacity. It seems to be a current limitation in android. If you want it to stop at 85% i suggest looking on google for a device called chargie.