Should I move from Google Analytics to Mixpanel?

It depends on what you're trying to do.

If you need to understand user behavior deeply-digging into individual users, building cohorts, creating custom reports without expert knowledge, or comparing user segments-Mixpanel outperforms GA. Its interface is more intuitive, and it makes this kind of analysis straightforward where GA makes it daunting.

If you only need basic metrics and conversion rates and want to avoid spending money on analytics tools, GA is fine.

The real case for moving hits if you're trying to connect product behavior to revenue and ad spend. GA can't do that work at all-you'll end up exporting everything to a warehouse and rebuilding the analysis by hand. Mixpanel (or PostHog or Amplitude) can be the central place where product events, ad data, and revenue live together, so you can answer questions GA was never built for: which channels actually bring customers who stay and pay, and what's your real cost per retained user.