Hi there,
This article perhaps answer your question:
https://complianz.io/does-complianz-affect-website-performance/
Rather than asking specifically about performance with GP, I believe the better concern is if your site is average or heavy like the article mentions.
GeneratePress as it is by default is pretty lightweight but that goes out the window once you install different plugins so things will vary between default, average or heavy.
Do you maybe know a lightweight GDPR Plugin that is compatible with AdInserter and is TFC 2.0 compatible?
We’re not exactly sure what works best with what. These are third party plugins that are out of our scope so we don’t exactly keep tabs of their compatibility with plugins like ad inserter.
But if I may suggest, since there’s performance context involved, you should try atleast 3 to 5 of the well known GDPR plugins and do tests for each and see which yields the best performance.
Here’s a few plugin options:
https://www.wpbeginner.com/plugins/best-gdpr-plugins-for-wordpress-simple-reliable/