Hey, re the switchbot ir minihub, learned ir commands DO go through to smartthings via the official integration, however it’s wonky - they will only go through to smartthings if you pick a device preset (so anything EXCEPT ‘other’) and THEN edit/relearn it with your remote.
Also only the power button goes through, so you essentially need to to create a new device in the switchbot app for every button you want to control, and then ‘learn’ it to the power button of each switchbot device.
Sounds like a pain but works v well once it’s all set up.
Here’s a screen of my switchbot app, where each button on my stereo remote has been learned to the power button of several separate speaker device presets (for the purpose of brining them all into smartthings)
I think the switchbot mini hub would be able to achieve what you want as long as you’re aware of the wonky way you need to set things up.