I've had same problem with my Samsung J7 Pro
This solution applies to every android mobile phone though. Its quite simple:
Go to Facebook App ;
Touch the 3 dots on top right;
Touch app settings;
Touch app updates;
Disable all three options ( auto-update Facebook and both notifications);
That's it.
If you are free from annoying notifications and intrusive Facebook updates.
Ps: same applies to Facebook messenger: click on your photo on top right, scroll down to app updates and disable all three options.
Cheers, folks
Neil Brazil