My setup at home is rather similar, with (at the moment) a 2016 MacBook Pro and a 2018 MacBook Pro but with a single wireless keyboard and mouse paired to one of the laptops only. As far as interference goes, there's a microwave less than 20' away, a cordless house phone only 6" away, and an Apple Airport Extreme Base Station about 2' away. I've never had an abnormal disconnect, and wake from sleep is immediate. Like Ric, and for the same reason, I always hit the Shift key to wake.I have two each of a Magic Keyboard and Magic Mouse 2 on my desk at home, where I have a 2019 MacBook Pro (for work) next to my personal 2018 MacBook Pro. No cordless phones in the house and the microwave is at least 60' away. Both keyboards and both mice constantly lose connection. It's really frustrating.
Two things strike me about your situation.
The first is wondering whether the multiple keyboards and mice could somehow be interfering with one another. Have you tried plugging one or the other or both keyboards in, to run in wired mode, or powering down one keyboard/mouse set to see whether there's some combination where the problem no longer occurs?
The other is to wonder why you continue to use Apple keyboards ("how poor my typing has gotten") and mice ("ergonomic nightmare," "user hostile") that you dislike anyway?
No argument for or against your keyboard and mouse preferences, which are different for everyone. There are so many other input device choices available.