The Z-Wave integration docs are helpful here.
Can I switch between the Official Z-Wave JS add-on and Zwavejs2Mqtt?
You can, but you cannot run them both at the same time. Only one of them can be active at the same time.
Since you have both add-ons installed at the same time, they are competing for exclusive access to the USB controllers, hence the “cannot lock port” error. You can’t simply re-configure the integration, because to re-configure it, the old server must be running, but if you try to set the new server that is not running, it fails to connect, as you’ve seen. Kind of a chicken-and-egg problem, and a bit annoying.
However, there are official instructions on how to switch from Z-Wave JS add-on to zwavejs2mqtt add-on: How do I switch between the Official Z-Wave JS add-on and Zwavejs2Mqtt?
I have also posted a guide on switching. Switching Z-Wave JS Addons with Minimal Downtime! Z-Wave JS (Official) to Z-Wave JS to MQTT (Community)
This problem is very popular in this forum…