Total Harmonic Distortion

Good Morning.
Hopefully i can get some suggestions here…though may be completely wrong forum. If so - my apologies in advance.

I’ve recently installed a portable home generator and after reading a ton of posts, apparently many of these portable generators can produce very high THD which according to many of the posts I’ve read…can damage electronics over time.
There are many videos available which show how to measure and calculate the harmonic distortion with a scope using a Fourier transform but after being out of technical school for (30+ years) isn’t a real option for me ( also don’t have a scope). There are power analyzer meters out there which can return a THD % result but are ungodly expensive and simply out of reach to a home owner…even if they did have the knowledge to calculate the THD.

I was wondering if anyone knew if any of these inexpensive hand held scopes might have an automatic THD % algorithm built in? I know these are probably just for hobbyist but if i could find one that has an auto calculation i’d certainly consider it.

For reference…i’m thinking of units like the SainSmart DS212…or the LM2020, …or the Thsinde TH944…all just over a hundred dollars.

Hopefully something out there for the avg homeowner!

Appreciate any thoughts.