My 2017 Model X had similar issues. It showed Parking assist unavailable message many times while driving on highways. It also displayed that autopilot is not available. However, this message was on for like 10 seconds and disappeared momentarily, rinse and repeat. My FWD open button on the center console was extremely sluggish, and sometimes it didn't work at all from inside. Fortunately, I could open the FWD from outside.
My firmware was 2021.24.5, and this started happening a few days ago, maybe last week. In my case, this issue is not directly related to the firmware update, as I updated it a few months ago.
Now I got a new firmware 2021.32.21 on Saturday and I installed it during the night. On Sunday morning, the issues persisted, and the firmware install failed. After a few hours of driving, the same firmware became ready to install with the yellow clock icon, so after I got home on Sunday night, I installed it again.
To my surprise, the install went OK and the issues were gone on Monday. In my case, the firmware update 2021.32.21 fixed it.
Hope this helps.