I've seen similar on some android apps I think, where it will ask you if you consent to sharing data with partners or something similar. When you say no there's a huge list of partners you have to disable one by one, it's probably 15 minutes of work to go through them all. I can't think of an example app right now, but usually it's on first install or something like that. Not sure GDPR applies to apps though.
Having personal information isn't always a bad thing, it would be really annoying if I had to fill out a form with my bank every couple of years to tell them my address, which hasn't changed and is a legitimate interest. Amazon telling everyone that I bought some athletes foot cream is not.