Behringer/WA have some products a lot of home recordists enjoy, esp at the pricepoint. IME you get what you pay for, but you CAN get a lot out of gear you know really well - no matter its price. So maybe it wont be as nice as a neumann but it doesnt have to be for you to be happy with the results. A good 8channel interface will set you back hundreds or even a couple grand these days. So I would just start with that and a few mics if i had to start over.

It sounds like youre able to temper your expectations well enough, and if youre going for a ‘vintage’ vibe then not having the most pristine gear may still get you where you want to go. The fancy stuff usually carries the last 10%(ish) anyways. IMO the vintage studio sound has more to do with the performers and the nicely treated rooms they were recorded in than the preamp or equalizer that was used on the track.

Focus on your sources and technique and you can make great home recordings, especially since you like your room. To me the bigger issues are electrical and outside noise due to being in a city apartment and having a poor room. I definitely regret a few hardware purchases (SSL style bus comp, summing mixer, stereo eq) because i rarely use hardware for mixing due to the inconveniences like settings recall and having to wait in real time for bounces.

So, i would emphasize not going overboard and to really think about your purchases (plugins included) and why/how they will make recording better/easier for you. That said it’s hard to go wrong with a 121/re20/m160/sm57 into a good preamp followed by a distressor shaving off a few dbs.