Release branches are fine (mobile apps, sure... web apps, probably not). Again, context is key.

You can still integrate to trunk as one would expect in TBD, no need for the delayed integration in Gitflow.

A common practice I see with mobile teams is they will create a 'release/x.y' branch sourced from trunk as part of their release routine (at some regular cadence, like 2-weeks).

If they need to (surgically) apply a hotfix, they can apply it to the release branch. Since the app store review process makes deploying immediate fixes impossible, a stronger emphasis on staging/RC QA is good as well.