I second this, grayjay.app is great. It does break TOS but you don’t have to login to the app, you can just add your subscriptions over and boom. It’s not FOSS but it’s not really too much of a problem since it’s supported by an organisation focused on decentralizing the big tech (FUTO) so I think it’s pretty safe to support using the app.
Well they want to keep the code under FUTO licensing but maybe we can hope they switch to GPL-3 :)