It's not necessarily just a 1 second delay they can completely disconnect requiring you to start the pairing process from the start, my Mac with Sierra or High Sierra would do this to my Logitech Anywhere 2 and then refuse to reconnect without a restart and then spend 5-20 minutes trying to get it to pair again. The mouse was fine, it was just a terribly buggy bluetooth implementation by Apple that they never bothered to fix, other MacOs variants worked fine, Windows worked fine, Linux worked fine, other computers worked fine, it was only that version of MacOS that had an issue. My HP bluetooth mouse would fail to connect on wake regardless of OS, the only fix for that was to pull the batteries (a pain) or replace the bluetooth module in the laptop to a different bluetooth version. In this case the mouse's bluetooth was poorly implemented and didn't like certain connections. Yet another mouse wouldn't work on any laptop without bluetooth 4.0 low power (this was part of the HP issue), I think this was a Dell mouse. I've seen glitchy movement as well on some wireless, others had extremely short range or they had interference. It's not like these parts were low end or unknown brands either.
Keychron, and I believe RK are pretty similar, and the Keychron is known to be EXTREMELY tall in front, it's at the very limit of ergonomic standards. You will likely require a wrist rest to keep from carpal tunnel issues, many have complained about it. My big thick all aluminum Filco, even with thick feet on the bottom is still several mm lower at the front switches. It's a thick boy. The "aluminum" case is also just a skin over the plastic case and the skin can mess with the wireless signals.
Logitech uses their own switches, which are not compatible with any caps and switches but their own.
As for other recommendations, I don't follow the wireless keyboard side, for one, there's so few options and secondly those that do exist I don't trust enough to recommend unless it's Logitech, which I wouldn't buy because of the switches. I do follow the wireless mouse side though (I only use wireless mice) and while I have had piles of mice the only ones that stick around are once again, Logitech. It's not that I like the company necessarily, but they spent a lot of time and effort getting wireless right.