I also like svelte. I’ve not used it for anything serious yet though for one reason: lack of libraries.
What you describe is a valid concern. I like keeping it more “vanilla” with svelte but any time I run into an issue of “Do I spend the next 2 hours building this, or just vet and pull in a library?” I’m left with the former option.
At this point in my life I’m not that interested in spending more time than I have to get something done.
So.. I just use react. No customer cares about 35kb vs 8kb or whatever people seem to optimize for. Even businesses in a developing country have 50-100mbps connection, and honestly most customers (even tech corps) don’t care about this stuff.