No recent apps, productivity tab, swipe down!

My DTEK60 has thrown a wobbly. Shortcut swipes don't work, I have no productivity tab, no recent apps , double swipe from top does nothing. I can hardly use it.

Started shortly after installing Firefox to allow me to upload pictures to my wife's Facebook as I am already using the FB app for my own account. It asked for Draw Over permissions but I couldn't get it to work.

It ran fine until the battery got low and it shut down. Hasn't been quite the same since!

It exhibits the same behaviour in safe mode.

I uninstallled Firefox but no joy.

I would call for tech support but I am traveling abroad and many time zones away.

All suggestions welcome, and thanks in advance.

have you rebooted it a couple of times? Is it charged fully? You should top off the battery at every chance. these phones should be draining until empty if at all possible

Yes rebooted many times, including hard battery pull equivalent.
I can't even get to the home screen to switch between apps!