Low watts, difficult resistance

Hello. I have an Elite Qubo Power Mag Smart B+ trainer - it’s a non-interactive trainer, but tracks wattage, speed and cadence. Hence ERG mode is not something that works for me in the training sessions. I got the trainer in December and it worked fine for a few months until one day, the watts I was able to put out decreased dramatically, and the resistance seemed much harder. The manual resistance is set to 3 as per Zwift instructions in regards to this trainer. A couple of weeks ago, the trainer wouldn’t connect to Zwift at all…the battery was replaced and it fixed that problem. It also seemed to fix the low wattage problem too as my first ride/training session after battery replacement seemed back to normal. However, the next day and half way through another training session, the watts dropped again and the resistance became difficult. I can barely reach 80 watts, whereas before, an easy ride for me was around 130w. I’ve done 2 ramp tests since getting the trainer…my first FTP was 125 and the now it’s increased to 147. I’m pretty sure if I took a ramp test today, It would lower to 70W. Nothing has changed. No settings have been altered. The only difference I saw was when my trainer connected before, it was listed as elite trainer 220, and it now either shows elite trainer 140 or just elite trainer. Anyone able to help me with this or provide advice? I’m supremely frustrated that I can’t come close to completing the pretty basic training workouts!!! Thanks.