I purchased a Nanovna ( tiny vector network analyzer) last year and it was a bit of a learning curve.
But they are easy to use once you figure them out.
The instructions leave a lot of information out.
The device is used widely in radio for complex analysis of antenna’s and rf filters and more.
Anyhow its an amazing piece of gear.
It also has a partner named the tiny sa
( Tiny spectrum analyzer )
I have one of those too!
Both being small and portable is a big bonus in small packages.
You can get both through Amazon.