I was in the same boat after 4 years of working and built a simple side project that solves a clear problem and now has several hundred thousand MAU (https://onthegomap.com) and costs a few hundred dollars a month to run.

My question is on logistics: Adsense brings in a bit less than expenses. Many users have expressed interest in supporting the project financially. Any recommendations on services to let people do that? One person recommended Patreon but that seems more geared towards artists.