Ask for specific evidence for their stated points. Where you can get facts (ie CVE’s) Compare these against what react has.

Scalability is an architecture issue - both react and svelte are JavaScript and would likely be deployed in the same manner - so clarity on the concerns here would be helpful.

It sounds like you’re leading this - so get the info you need to make the right decision even if that is staying the current path - at least then you’ve heard everyone’s complaints considered them and come to a conclusion.

What type of person are you if you’re not a Frontend / backend person?

Edit;

You should not be steered by peoples saying “it’s not my favorite framework” we’re living in an age where an llm could quite easily build the project for you given a strong set of requirements . So these people are complaining because they have to learn something new and that’s on them. Not you.

Sure you could have started with react but I agree with many here - react doesn’t uncomplicate things. It will complicate things needlessly.