Yeah, switch testers are meaningless. The switches you have extensive experience with (in what builds?) are pretty zzzzz, IMO, And there’s a lot more to the equation than just the switch anyway - as I said, MANY factors go into the typing experience.
It sounds like you haven’t tried a well built custom - if you are looking to stay engaged in the hobby and discover sound/feel beyond Topre, that’s where you want to go next. While some people do get into it for their Instagram accounts, I can tell by your comment about shiny cases that you’re ignorant to the impact a nice case can have on the typing experience. Or not even necessarily nice - just differently constructed. Your basic tray mount has very different properties from a gasket mount, or a top mount. And plate material has a huge impact on feel as well - and some cases use plates built into the top, which can have its own set of properties and typing feel. There are Keycult boards selling for $2500+, without switches or caps. And they look like plain ass black TKLs. People aren’t paying that kinda money for how a KC looks.
Like I said, it’s a deep rabbit hole, and can get very expensive. But to your original question of “how do you stay in the game” - this is how. If you’ve got an FC660 in a Heavy6 I assume you’re open to spending at least a few hundred bucks on a board, and there’s a lot of fun to be had and super nice customs to play with in that price range, without needing to spend thousands on a KC or a Jane.
Again, you may just be a Topre guy at the end of the day. But if you want to stay with the hobby, you owe it to yourself to learn to solder and start experimenting with various custom builds. Soldering is easy and the equipment is cheap, so that’s no excuse. And anything you buy can be resold on mechmarket in literally minutes, the demand is so high. Hell, searching for the gear on mm to put that perfect build together is part of the fun, IMO. But if you’re just looking for the best typing experience off the shelf, I agree that Topre can’t be beat.