@slowcyclist Thanks for your reply.
I've been away for quite some time, so apologies for the delayed response.

Since the suggestion involves the read-only rootfs, how did your OTA-5 update turn out?

I am not able to mount the image as writable, by the way. I've done it before but not on a UT device, so I am not sure if there is a better syntax. I used it as a sign not to tamper with rootfs, for now, until I am able to confirm that OTA updates are not going to be affected by the workaround.

I've only observed that the inability to connect to the hotspot can be related to the WiFi WPA-PSK security, as well. It may be a good idea to have some options regarding WiFi security, but it will have to be a bit more universal, as in all devices have them, even though, at the moment, only our Xperia X devices have this hotspot issue, at the moment.