Inventory toolbar has disappeared

I am playing on my phone (s24ultra). I haven't been on my world for a while. When I went back a couple of days ago, I discovered that I do not have any inventory toolbar displayed on my screen. I tried to fix it via the parameters but without success. I created a ticket but the help was not understanding my issue hence inviting me to raise my concern here.
Maybe linked to that issue, I can travel through my buildings and underground without any hinder. I can see the entire world from below the surface (see attachments).

My world is on realms (on world only).