That is not the consensus. Z2M supports more devices than ZHA, but I’m sure you can find a few exceptions.
My general take on the two is here.
I’d recommend getting the dongle, use it to run z2m side by side with ZHA, test a few devices, and then decide where you want to be long term. If you decide to keep z2m, migrate at your leisure - you can move devices one by one. If you stay with ZHA, remove z2m and migrate ZHA to the new stick.
For z2m the ZBDongle-P is recommended. The ZBDongle-E is supported, but is currently labeled as experimental - it is mssing backup/restore functionality.
But… One advantage of the ZBDongle-E is it can be flashed with the multi-pan firmware and be used for both Thread and zigbee2mqtt.