I'm a software developer of 30+ years.
Recently deployed Magento 2.3.7 on Ubuntu.
Looking forward to contributing changes before the first upgrade in 6 months or so.
Welcome to the community forums!
The best way to start is to ask and try to help other into the forums so you are in the right path.
As you can imagine, you'll find information on StackExchange too and you can start diving into the https://devdocs.magento.com/ not only for learning but to correct and improve the docs.
We can't forget the powerful User Guide: https://docs.magento.com/user-guide/getting-started.html.
Another recomendation could be to be aware of Magento issues on Github: https://github.com/magento/magento2/issues (if you are technical, of course).
Also, you should read this post: https://community.magento.com/t5/Welcome-to-the-Magento-Community/Start-here-and-hello-from-me/m-p/5... (in particular the guidelines) and if you are not sure about how to use the forum you can read the FAQ: https://community.magento.com/t5/help/faqpage.
If you need information related with GDPR, you should check this: https://community.magento.com/t5/help/faqpage/title/gdpr
Finally, you'll need to get your hands dirty with the platform.