ZigBee Gateway question: CC2531 or ConBee?

I am running the RPi 4 with OpenHab.
My goal is a smart home setup without any cloud or internet connection.
Therefore I am looking for a good supported ZigBee Gateway for openhab.
I already own the ConBee II USB and a preflashed CC2531 will also arrive soon.

As far as I understand the ConBee I have to use the software deConz and the openhab Deconz binding. Pairing devices will be done in deconz and then I can discover Lights and devices with openhab. Correct?

If I use the CC2531 version I can use the zigbee binding in openhab. Does this mean the deconz “software layer” becomes obsolete? Is this way superior to the conbee version?

As far as I understand ZigBee bindings, it involves regular development to make devices compatible. For conbee I could find a github repo and a compatibility list.
How is this managed in the OpenHab Zigbee binding? I used google but couldn’t find something which helped me.

as I did not use Conbee, I only able to answer about CC2531:

if you use the CC2531 with the zigbee binding, no additional SW-Layer required.
All can be done in the OH UI.

correct, i installed the Conbee II USB Stick today on my Synology NAS. Once it was up and running with the Phoscon App, I connected it to the Deconz binding in OH. The OH connection works well, the devices set up in Phoscon are detected right away.

According to him ( CC26X2R1 - der beste ZigBee-Coordinator? | haus-automatisierung.com [4K] - YouTube ) I would buy the CC26X2R1.