Earlier quoted context omitted.
I have tried to use sveltekit once and turned around in 20 minutes as routing is severely limited. All I wanted to do was to route based on domain, with a different set of routes for one of the domains. Not exactly complicated or uncommon, but not something you can do with the sveltekit router.
This is gone over in the github threads about such a feature - basically, as two different projects semantically, the best thing is to create two different projects physically, in a monorepo. All the code-sharing with none of the additional complexity.
Just curious, I have no experience in svelte. It does sound like a major limitation.