I can’t believe that someone did not mention GNS3 and GNS3 Vault. When I studied for my CCNA I used GNS3 a ton to fully get all of the required knowledge down. As for burn-out I just force myself to not do anything productive, minus the working out, for a day or two. It really helps with stress.
I do use GNS3. Honestly though, I have been putting all my time and energy into Python and learning to code.