Requiring a paid login is certainly fine as long as the client application is entirely free software. Ads are probably fine if they are shown using free softwa

Requiring a paid login is certainly fine as long as the client application is entirely free software. Ads are probably fine if they are shown using free software but will be marked as an anti-feature. Same for tracking. In app payment is probably fine too, and will not be subject to a 30% fee or something.