Strap change on vintage Cartier Tank

Recently came across this vintage Cartier Tank that is my mothers, which I would like to put onto a leather strap.

Has screws on one side and nothing on the other. It’s not anything I’ve come across before and I can’t seem to get the screw to move one bit.

Does anyone have any idea how I would go about a strap change for this? I searched everywhere online and can’t seem to find anything that helps.

Any input is greatly appreciated!

Yes. My mother told me her father bought it for her when back in the 70s. It was actually just sitting in the safe, and I’ve never seen her even wear it before. I was kinda questioning its authenticity at first but its keeping time well after all these years. But I also have 0 experience with Cartier and can’t get the case back open either. It’s on this funky aftermarket vintage gold bracelet. If there are any Cartier experts on the form any input is appreciated.

Is it possible that it may have been installed with loctite?

I really doubt it was. I was hoping someone on here has experience with this Cartier tank, but I rarely see Cartier watches posted...