How many devices of each type do you have?
12 Iris 3320-L Door Sensors, 3 Iris 3326-L Motion Sensors, 4 GE Bulbs, 1 Plug (acting as repeater).
LQIs range from 98 to 36. Brand new batteries show as 27% while slightly used batteries are flashing as nearly empty (when reconnected to Smartthings, they show as 100%).
I never had a repeater when this set up was working flawlessly for years on SmartThings (not counting the bulbs which weren’t powered most of the time). My understanding repeater becomes mandatory at 32 items, I’m well below that.
It is even calculated different for different silabs chipsets.