Question: I just got a new work laptop. I would like to seamlessly switch my bluetooth devices (headphones, magic keyboard, touchpad) between work / personal Macs without complex repairing.

Has anyone solved this problem?

Ideally, I would love it if my bluetooth devices just paired with the computer docked into my dongle that connects to my monitor / power. Like if there was some kind of USB bluetooth controller that exposed my bluetooth devices as USB devices to whatever was connected to it, that would be awesome. But I haven’t found anything like that. I’m curious if people have different solutions?

It would also be ideal if this could be used for other bluetooth devices, ie seamlessly switch headphones...

Answer: 
Software KVM solution such as Synergy, Across, others... But you would need permission from Work to install the software on the Work MacBook Pro.

That would work for the KB/Mouse/Trackpad but for the bluetooth headphones they would need to support multiple devices as Allen said.

Your employer may not like the idea of a software KVM. Your mileage may vary, depends on the employers IT / IT Security departments.
I've discovered [AirBuddy](https://v2.airbuddy.app/) (a lightweight Mac app) that solves this problem seamlessly - it's not free (£15) but works really well and the documentation is great. I use it across two Macs with a different iCloud account on each (meaning I can't use Universal Control) with a Magic Keyboard and Magic Mouse and can't recommend it any higher. It does exactly what it says on the tin, every time and for a reasonable price (all pretty rare imo!)