Vaadin Flow, hence Jmix, doesn’t support react components, but Flow can integrate with any WebComponent and use even plain JS component (as discussed here).
Speaking of your particular component, it has non-react version that can be integrated using approach from the topic above. E.g.
Add the following dependency for the Server side part:
@NpmPackage(value = "seqviz", version = "3.9.1")
And the following import and component initialization in the client side part:
import {Viewer} from 'seqviz/dist/seqviz.min.js'
...
ready() {
super.ready();
const viewer = Viewer(this, {...}).render();
...
}
Gleb