I am having this dilemma whether I remove xdg-desktop-portal entirely in the system or just let it running in the background doing nothing i guess? but removing it will also affects gtk4 which some apps relied on. Although I am on a hunt for qt alternative with the said apps since I do not want something in the middle handling task for me that it should be a gtk thing only. Can we force it not to run and be able not to cause some issue in the future?
There are many things that require xdg-desktop-portal to function. In most cases, you should not remove it.
Is there a reason you want to remove it?
You can certainly remove all the qt* packages but anything based on Qt will also be removed or not function.
This will give you an idea of the dependencies as well as other apps that require it:
Unless you have a very good reason to, best to leave it alone.
If it is causing problems, then help us understand what so we can troubleshoot.
my reasoning was i want them to function as it was before. doing things on their own way like file-picker, or document etc. now it is automated and i dont like that. And btw i am X11 user.
finally i am now gtk4 free desktop so I decided to ditch that portals in my system.
although i ask AI about the disadvantage of having portals the answer i got scared me.
there is info below that maybe i want to use and that is masking the services but I am gtk4 free now anyway 
though i’m not entirely sure of that info accuracy and for those who read this.. I am X11 user so be warned.
putting any faith in that is foolish. I find it’s 50/50 accuracy with Linux stuff.
why would you want to be gtk4 -free in X11? Just curious. xdg-portal makes a lot of good things function, too.
2 cents
Instead of completely removing it, first try masking the service.
If there are no issues or side-effects, then great.
And if yes, simply re-enable.