My highly customizable split mechanical keyboard. Not naming the product because it's my fault that I regret it. It's very high quality and does exactly what it claims to do, and I'm sure many users are happy with it. It cost nearly $400.
It's a ~60% keyboard, which means it's missing a lot of keys. Notably the F keys and the navigation keys (pgup, pgdn, ins, del, etc). There are ways to remap the blank keys to what you really need, and of course there are all the key sequences and chords you can use. But you have to memorize this stuff, because many of the keys are unlabeled by necessity.
I use it on my PC, Mac (work), and Linux (steamdeck). It's a lot of cognitive burden remembering shortcuts and which modifier keys do what on which OS, with the added headache of having to remember which unlabeled or remapped keys are which modifier keys. I love the feel of it and for normal typing it's great, but anytime I stray from the basic keys (A-Z, numbers, etc) it becomes difficult. I end up doing embarrassing things like using right click on my mouse to do things like copy/paste.
If I was on exactly one OS all day long, I think I could make it work. But juggling 3 is annoying.
If I could redo it all over again I'd realize I didn't need a split ergo keyboard, and would have gotten something more traditional.
Keyboards are easily replaceable - why not just leave off from the sunk cost here and get one that's more to your liking?
My experience has been a bit better than yours. I had the same concerns you've raised here and opted for a more standard layout and got a Mistel MD770, a lesser known brand but it was important to me that the layout is familiar and it has F keys and honestly it's been great, had it for about a year now. I use it on all 3 OSs too. I'm now looking to buy another one for the office as it's too much of an effort to carry it and I've been looking for other keyboards but there aren't (m)any that have standard layout (no columnar stuff), split, pre-built, F keys and ideally hot-swappable switches. The closest is probably dygma raise but it doesn't have F keys which is unfortunate. I think I'll end up buying another MD770.
If you spend the day working with F-based applications, this may not be a solution. But if you require those keys for tasks like renaming files, etc it may be enough to configure SuperKeys on the Raise: keeping the key pressed for 250ms can trigger any other symbol, including the Fs. It might be more natural than switching layers.
I also bought this not naming split mechanical keyboard that costs nearly $400 :)
Not entirely dissatisfied, but disappointed.
Functional keys, cursor, home/end/pgup/pgdn are painful. The default layout is complete garbage. I made 3 iterations with functional keys over 4 months, still struggling. I connect the kbd to the laptop via the monitor, and recently noticed myself switching to the laptop to get things done quicker.