Gaming

I think in this case AM4 is fine. I recommended it because OP mentioned the price was a bit much, and AM4 at the moment gets you a lot of value. Especially given they are someone who plays indie games primarily with some heavier games occasionally and isn't on all the latest AAA games. I'm actually very similar to them where I'll play the occasional AAA game, but I mainly stick to Minecraft and KSP (which is stupid CPU intensive). My R5 3600 was more than enough for this and my upgrade was 100% unnecessary, so the 5600X should last them quite a while. There is also a decent upgrade path from a 5600X to a 5800X3D or 5900X3D.

We're starting to see gaps between generations get smaller as Moore's law fails, so I think parts are going to start lasting a bit longer now anyway. Hell, my 4970k lasted me almost 7 years, and my mom ran it in her work PC I built her for another 3 after that.

I honestly don't think either path is a bad one, just up to them if they want to save some money or get a little bit more upgradability.

I only grabbed a 5800x3D at boxing day last year, because I'm running an AM4 board and it was one less thing I'd need to update, well that and I'd have to also buy all new ram and buy in at the peak of pricing.

If I was building from scratch today, I would unquestionably do an AM5 build. If I had an AM4 board and I was otherwise happy with my RAM setup, it's still a pretty tough choice. You aren't going to get as much time out of it at this point vs AM5, at least I don't think. It also means your next build is going to almost for sure need to be entirely a new build, save for the case, the power supply (if it's big enough) and maybe the storage (which hopefully will be larger and cheaper by then). The hard part, too, is they are already talking about a release window for AM6. So maybe AM5 doesn't last as long as AM4 does, making this all moot. But you'd probably still have a refresh window with AM5 at that point, and not be totally obsolete.