However majority of projects I noticed is used as monorepo (mostly Nextjs), which is nice, but I would still prefer to embrace split between BE & FE, as thats the frequent case for others REST, GraphQL etc., especially for bigger projects/companies.
BE boilerplate - https://github.com/mkosir/trpc-api-boilerplate
FE boilerplate - https://github.com/mkosir/trpc-fe-boilerplate