Few Questions: How likely is this to be blocked by uBlock Origin/Firefox private mode (easy-list etc). Do they have any rules what they consider to be 'ethical analytics'? How much overhead does this analytics package have on page load.

Have you considered a free tier for up to 1k page views a month for example?

How can this track conversions for A/B testing? This is one of the most common usages of analytics in my experience. Is there a way to have user based conversion tracking whilst still being GDPR compliant?