Agreed. We got used to thinking of any Javascript as "business logic" rather than "presentation" because it's an imperative language, but React/JSX are tailored to using JS in a way that acts more like presentation. If you write it imperatively, it won't be idiomatic React, and sooner or later something will break.
So it may help to think of JSX as using a functional subset of Javascript. It's not, and that veil gets pierced pretty often, but the better you contain it, the more you can effectively use both Javascript and HTML together as part of a single concern.
Using Redux with sagas even further separates out the most side-effecty parts of it, though sagas are really heavyweight and I'm still not certain if I think they're worth it.
Sagas are a great power tool, but most Redux apps don't need them. That's why we opted to include thunks out of the box as part of our official Redux Toolkit package:
So it may help to think of JSX as using a functional subset of Javascript. It's not, and that veil gets pierced pretty often, but the better you contain it, the more you can effectively use both Javascript and HTML together as part of a single concern.
Using Redux with sagas even further separates out the most side-effecty parts of it, though sagas are really heavyweight and I'm still not certain if I think they're worth it.