You might want to reconsider ”no data ever leaves your machine" from the post :)

Given your target market, have you considered looking at Bugsink?[0] sentry compatible. still not local, but at least you won't have to additionally ask your customers to trust sentry/posthog.

Disclosure: that's me

[0] https://www.bugsink.com/

Bugsink looks interesting. Will take a look.