Firefly III is an option, but I found it difficult to set up and the importer tool works well for Europe but not the US.
You could also just create your own Docker container which has Skrooge, GnuCash, or KMyMoney in it. I have done this with Skrooge since it imports data well and is simpler than GnuCash.
Yes, just because the source code is available doesn't mean it is licensed for others to take. Now we have AI tools that have scraped the web for all of its content and won't see the difference between source available, open source , and free and open source. It is possible that those who use AI tools could be unknowingly using code without the license to do so.