Any advice you would like to give me to deepen my knowledge?

Hello, I am currently looking for a first job in a mechanical design office and I am therefore taking advantage of the time I have between my research to deepen my knowledge. Therefore, I would like to know if you know of any Youtube channels that specialize in CAD and in which I can find course videos. Or websites that offer courses on the subject. I did some research on my own and I found 2-3 interesting channels and websites.

My second question is  on which themes would it be interesting to deepen my knowledge and which could be very useful to me in the design office? For the moment what comes to mind is: 
- Know how to side a part correctly and make a good functional dimensioning

- Knowing how to choose a material

- Know how to use the force simulation module on Catia and Solidworks

- Know the different manufacturing processes

 

And finally, my last question is, in your opinion, what are the most useful modules on Catia and Solidworks in the world of work?