I use Accubattery on my Pixel 7 Pro, and it's reading 99% after a year. I typically wait until around 40% to charge, and when I do, I charge to 100%.
Do you habitually charge to <100%, like maybe 80%? If so, I wonder if that might confuse Accubattery's algorithm (although that would seem unlikely, since you'd think that the devs would know that battery-conscious users are more likely to try to follow the 40-80% guideline). In any case, if you don't usually charge up to 100%, try doing that for the next few cycles and see if the battery health changes.