I can relate too. I reached a point (as a software engineer), that shitti functioning software annoys me so much. Functions that are just annoying that no one really asked about, functions that are so bad designed that I really ask myself who the beep is really responsible and accountable to sign off this crap.
AI should help us really make this small but time consuming implementations better too, not just shipping more and more crappy stuff.
The Bible is hardly based on the clay tables. Genesis, the first book of Moses, tells the story of the flood, which the Sumerian refer to as Gilgamesh.
IMHO there are tests and there are tests. I had to work with codebases that had awful tests. They broke frequently because they were badly written. They used a lot of mocking when mocking was not appropriate. This tests were written for the purpose to have tests not for the purpose to really test the domain. I do not write tests for simple cases, like method in class A just delegates to method in class B.
For a one man show - go on do not write tests, especially if you do not know where you will end up with the software. But in teams I find a lot of value in (good written) tests, preventing bugs and documenting bugs. Sure you can over-engineer it, as everything else too.
BUT working without version control? Good that it works for you. I think version control is one of the MUST USE tools.
You can have your own skill repository with Skillshare and sync across agents (symlinks or copys).