Those who actually use it, can they write down a simple comparison?

Those AI features are completely absent from Affinity. That said, Serif was recently bought by Canva who have AI features in their web suite, so I expect those to come to Affinity at some point, possibly requiring a subscription for cloud-enabled features (regular Affinity feature set will remain pay-once and offline, according to announcements). I hope some AI-supported upscaler will come to Affinity. I currently use some free web tool for nicer upscaling.

Also, Affinity apps don’t support file format plugins at all. AVIF and HEIF aren’t supported, so you’ll need external converters to open those.