RBK852 Unable to connect to admin web/app

A bit like the issue with the RBRE960, I now longer can connect to the admin ui of my RBR850 anymore, and the app doesn't seem to find it either.
I suspect the issue started May 23rd, when I got a notification from the Orbi app that "Your RBR850 has been updated to the latest firmware, V7.2.8.2".
I'm still able to log on to the admin web on the satelites, and they both shows version 7.2.8.2 also.
I do see that 7.2.8.5 is the latest version, and has been so since december, so kind of strange that it chooses the version before it for auto upgrade.

I have, as in the RBRE960 case tried to restart, power off (removed for minutes). And when plugging the power again, the power led turns green, and then I get a white blinking led around the router. After a while it stops and the router routes traffic, but no admin ui or ability to connect the app.

I tried the next step, remove power and all ethernet cables for minutes, then gave it power (still without ethernet cables connected). Same bootup sequence, blinking white lights for a bit, then purple (indicating no internet). Connected the fibre, and the purple light stopped and the router was routing again.

Only missing the ability to admin the router.

I was thinking about upgrading to 7.2.8.5, but last I tried something like this, the admin web needed to be available, so are there any way to push the 7.2.8.5 to the router with no web admin?

Or are there any suggestions how to fix otherwise, except for factory reset?

I do understand that last effort may have to be a factory reset, but I'd hate for that to happen, as there will be alot of configurations to be done to get it back where it is now.