My problem is to find a source for a comprehensive, deep-dive, way to learn Figma. I’m new to UX and it’s hard to learn it just by using it and watching random youtube videos or some courses. What’s been your best way to learn it for yourself?
Mainly learning by doing was my way but also with the addition of random youtube videos and articles. Listen/read and repeat. In the long term that worked best for me. If you stuck, you can use this forum and ask for help 
At the beginning, i learn all basic from figma youtube channel. Practice daily, master every tools in figma. Explore more deep dive skill, like auto layout, master component, variant…etc.