Back to the topic at hand on Why You shouldn't use JQuery in a framework?
Because it'll just make your app heavy.
Everything JQuery can do, VanillaJS/JS/TypeScript can do better and faster.
Frameworks already has its OWN LIBRARY. JUST READ THE DOCS!!!
And finally... JQuery is no longer relevant as mentioned above. It was a band aid solution on a wound that's already healed. It served its purpose...DONE
Alright! Little disclaimer... I'm not telling developers or aspiring developers to not use JQuery at all... But at the same time decide for yourselves whether its still relevant.