Note that there is a repo issue about this: https://github.com/nim-lang/website/issues/226
I think plausible is an excellent alternative, one of the things I like particularly is the fact that dashboards can be made public (as shown by Hugo)
I actually reached out to @dom96 some time ago and he said he would open to add plausible analytics on the website. I think this could be a first step before trying to remove Google analytics.
I offered in the repo issue and stand by again that I would be happy to use my subscription if needed. At the moment my subscription is a bit clogged by a unexpectedly viral translation of wordle in Italian that I made a few days ago to play with friends. I will consider this again once excitement about this will decrease (as I expect it will).
Also plausible can be self hosted and in that case we would only pay for server costs (I probably should consider that, have been lazy for the moment).