Any recommendations for how to practice Magento 2 when not working? i.e. it's easier when working as you're presented with real life task, issues, clients etc. but when practicing at home, I'm just not sure of the best way to keep harnessing and improving Magento 2 skills etc.
Your question is a bit ambiguous, magento has a lot of aspects, frontend, backend, architecture and each section needs its own research.
You can start as a newbie with following:
There are a lot of articles available you can read online specially weblogs, I suggest you study the following links:
Also following this YouTube channel really helped me: https://www.youtube.com/c/AlaaAlMaliki
after you got comfortable you can study the dev docs: https://devdocs.magento.com
after again you spent some time and got comfortable, look at the most voted users here on magento and look at their question and answers it is a great resource to see what skills you are missing.