Buying hardware that can run open firmware is nice for future proofing in case the vendor goes sideways with their firmware. I do the same for routers with OpenWRT.
That's... not true. There are many items of the Tuya ecosystem resistant to flashing with another firmware.
Hm, no not really. I have a bunch of remote controlled sockets that can't be reflashed with Tasmota and that require a ridiculous number of hoops to jump through to access including enabling 'developer mode' and access from a bunch of IPs in China. No thanks... really annoying because it was exactly one of those comments that caused me to buy them in the first place.