I can recommend nestjs.com. Nest (note: not nextjs) is a framework for building webapps/microservices in TS. If you build an app using nest, the framework is going to give you a level of structure that you may like.
In terms of learning by reading nest's source, I don't think it's the most readable code out there - but there's certainly a lot to learn about abstractions. On the opposite spectrum, if you're really starting from 0 maybe find a few apps done in nest that go a little beyond the basics covered by the tutorials.
(I have no affiliations with nest, I'm just using it for my own project and I certainly learned a lot from the framework.)