Hi Feigr. Welcome to Geekhack.
What switches have you tried? I would suggest that you get a switch tester before you pull the trigger on a specific set of switches, especially when it comes to MX browns. People seem to either love them or hate them. I'm in the latter group. If you really want to get a kit together right away, I like Aliexpress and KPrepublic for parts. For switches, Novelkeys is usually pretty good on both prices and selection, although I think a lot of switches may still be entirely sold out in many places. Sometimes, depending on what you want, Amazon has kit boards at decent prices, sometimes even with U.S. shipping. A lot of people use KBDfans, I have not (I have yet to actually assemble a kit board yet myself, not my focus). KPrepublic has a
130 switch tester which is a good value, and covers at least most of the more common OEM switches, and a few unusual ones to boot. It should at least give you a relatively good idea on what types of switch you're going to like, and help narrow down what qualities within those categories you seem to value.
Sorry I'm so late with the welcome, I haven't been on Geekhack much in the past few weeks.