Today I saw that I did 3h30min on my phone and still had 57% on One UI 6(to be specific it carried up to 85%), while on One UI 5.1 I did 3h30min and had between 30% and 40% battery(which also carried up to 85%) , I was very impressed. And I also noticed that after the update it freed up space, before it had 61.7GB occupied and after the update I saw that it had 55.4GB occupied, equivalent to 6.3GB free. This is all on the A54.
If you update to One UI 6, and factory reset, you will release a majority of the bugs you get from a drity flash, and your battery life will be wayyy better.
I recommend a backup of your things, or transfer to a PC all your goodies, then factory reset the phone if you’re having bad battery life, but I get almost 20 hours of Acreen On Time with my S918B/DS running Dr. Ketan