PowerWalls and UPS

I was having a problem with my CyberPower UPSs, two of which are quite new and the other 2 are a few years old. A friend of mine found this discussion which is extremely interesting and tells me what is going on. https://teslamotorsclub.com/tmc/threads/powerwall-2-ups-connundrum-and-solution.130085/

Now I've got to replace 4 UPSs which is already pretty expensive, and way too expensive when working less than 50 percent full time. However, this made me realize that my UPS plan can be changed now that I've got a PowerWall. It doesn't work as a UPS, however it does condition the line a bit. Turns out not as much as I thought.
https://teslamotorsclub.com/tmc/threads/powerwall-line-conditioning.116915/

So now I'm back to replacing all 4 UPSs, but at least I don't have to cover everything for long term power outages, just short blips, so that should reduce the cost of the UPSs chosen, although I have to make sure the frequency range is suitable.