I'm looking to use Vite/Rollup to just transpile files from .ts/tsx to .cjs or .mjs files without bundling everything into one big file.
I know that it's the point of Rollup to roll everything up into one file. But Rollup is also handy in providing a bunch of presets to deal with e.g. Typescript files and Preact.
I guess you could try
output.preserveModules:https://rollupjs.org/configuration-options/#output-preservemodules