Once I tried to create my own front-end framework from scratch. I created signal library, mounting/unmouting, context etc but never able to write v-dom diffing or using existing vdom libraries.
Then I decided just implement my API on top of Preact. Preact did vdom-diffing for me and mounting/unmounting which was enough for my need.
The final project looked nothing like Preact, it even had it's own context system, data loading, signals, setup + render and context which just hooks itself into Preact Context but taught me a lot about how a front-end framework work.
That said, it's still a worthwhile exercise that one can learn a lot from.
Do we want money or do we want to get the pleasure of being an engineer and make money as a side quest?
There was a video of tsoding about why he doesn't have a job, he says "when I have enough money for my needs I just go into coding instead of working". I like his vision. He likes coding for the sake of programming and earns money as a side quest.