Like internal tools, consumer facing tools, content site, social site, etc. Is it an MVP? Rebuilding an old system? Is this a build it, ship it and move on? Or build, enhance and maintain for foreseeable future? What's required lifetime of it? What's the desired lifetime?

As well as resources. You want to use different setups if you are a single person compared to a team of 15.

Generally speaking the smaller the team the simpler the architecture needs to be. And the larger, the more isolation you want between pieces.

Personally I currently like Rails and React best. Both are fairly mature frameworks and work well together. Not to say there aren't better alternatives just those are the two that have worked best for me. There's so many good options that no one knows them all well enough to make a fair comparison.

I think Rust is very promising as a much faster alternative to Ruby and expect to switch over to it sometime in the next decade. But I don't feel the web frameworks for it are mature enough yet that I can justify a switch to it to my employer.