I have a 56V electric lawn mower. It takes nearly the full charge of one battery to mow my slightly larger suburban lawn. Trimming and blowing and what not gets handled by my second smaller battery. My largest battery isn't even the largest they make for this model line. I've been on the same two batteries for five years now. I use E-Go.
I'd say your system is just undersized for your needs. Judging by having two batteries, it sounds like your system is one of those based around hand power tools batteries and then attempted to scale those up to lawn mowers. I've mostly heard bad things about this path. There's a lot of other experiences out there.
We have a large lawn, and a pile of broken eGO products. They wear out fast and cannot be repaired.
We started replacing them witg Milwaukee lawn tools. We frequently hit overheat cutoffs, but haven’t broken any yet. We do have a pile of dead small eGO and Milwaukee batteries though. These days, we only buy the biggest capacity we can. Those tend not to die as fast.
Electric is clearly the future for this stuff, despite our problems. The remaining gas powered stuff is all > 10HP.