First of all you are trying to use the construct url column incorrectly. It is not for building your own links into your app by putting whatever you want in it. That’s just not how it works. It’s for building links to link outside of your app. Even then, it has to follow the correct format rules for how those urls should be constructed. You can’t just make up a link to a page and expect it to work. This same topic has been discussed here.
If you are attempting to link from your notification tab to your feed tab, you are going to have to either save the deep link that glide already creates for you and works. Or you need to create a relation that links a common value in the notification sheet to the same value in the Feed sheet. Then you can link to screen through that relation, or create an inline list on your relation, or whatever you want. I would recommend the second method, since it would be much more reliable.
What you are trying to do with the Construct URL column is just not possible and not at all how it is meant to be used.