Not sure if you’ve seen this but it may give you some ideas/leads.
This cheap logic analyser was recommended to me a while back and it’s worked well so far. I haven’t used it for PWM though. It can be used with Sigrok.
AU $7.78 14%OFF | USB Logic Analyzer 24MHz 8 Channel 24M/seconds Logic Analyzer Debugger For ARM FPGA Logic Analyzer Logic 24M 8CH https://a.aliexpress.com/_mOuGQtq