Yes indeed, the limit is 50 which is of course enough to fully profile "regular people" who only have a handful of apps. Also don't forget, Meta/Google/TikTok/WhateverPalantir are updated weekly which means they can tweak their LSApplicationQueriesSchemes list and cover even more apps if they want to.
Are there legitimate reasons why an App should know I have installed?
Back before Apple allowed users to set the default browser I had a feature in my app that presented a list of installed browsers when a user opens an external link, giving them the option to choose where it opened.
Android gives me that option at the OS level.
E.g if gmail knows that you have maps or chrome it can deep link you into a particular view instead of opening safari.
At the OS level, Android gives me the option to open links in the corresponding app.