If you have 3-months - https://pythonmorsels.com has been a godsend for me when drilling on the fundamentals of the python language. I guarantee that if you are relatively new to the language, that you won't run out of (A) Interesting exercises, (B) Fundamental language concepts in less than 30-45 days, even spending 2-3 hours/day. Just knock off 1 or 2 a day, and then come back a couple days later, and, without checking into the hints/guidance, try and recall how you solved the exercise the first time - with zero checking into SO/exercise hints. I got 10x more out of the second solve, doing it from only my knowledge. If you can keep that cadence up for even a month - you will have at least the language fundamentals down really, really solid - then you can pivot to various algorithmic solves in the language, or, if there is a particular front-end/back-end/etc.. framework that you need to know - drilling into the characteristics of that.

Trey Hunner is one of the more gifted speakers - and he's really laid out a great exercise and test-coverage plan.

The best thing I can say about pythonmorsels is that, every 15-20 exercises, I look back and realize how little I actually knew. Going through all the exercises is easily the equivalent of a full-semester "Introduction to language" course at a college (minus the algorithmic elements - this is a "language concepts" site)