Interesting point - I had no idea they offered Zigbee kit after seeing the debacle with the original Tuya cloud integration, and the removal of ESP82xx. ISTR the Tuya cloud integration got updated a few years later.
If you want a longer read comparing different protocols, get a 
and have a look at my ramblings...
My architecture plan is to move from Zigbee + Z-Wave to Matter/Thread + Z-Wave but the questions over the IKEA Matter firmware are worrying - even Frenck mentioned Matter issues on the 2026.05 livestream! (and remember HA is used as a compatibility baseline test)
TL;DR Either YOU pay for the manufacturer to test kit and get certification or YOU test kit with sweat equity with custom quirks and workarounds.
I started with DIY PCBs and importing US 110V X10 kit and modifying it for UK 240V so have some history.