PowerWalker doesn’t have the sysDescr_except mentioned on the post from OP. But the sysObjectID is different, even though the MIBs given on the PowerWalker website are .1.3.6.1.4.1.3808.
It is very common in the UPS world to use the same SNMP card for a lot of devices and brands, making it difficult (and sometimes impossible) to differentiate them …
For the first one, I guess that the “except” was added to prevent the detection by this YAML and probably match another brand/device using the same card with a different name. So removing simply is probably not the solution (will break the other one). Finding the PR where this except was added will probably help find the other (if any) OS that is similar, and from their, you can decide to create another exception or include your device in one of the existing ones.
For the 2nd one, if it is detected correctly, I would stick with it, simply to avoid creating a new scenario like the above. It will specify another vendor name but your UPS will be detected as expected, which is what matters at the end of the day.