Good read! I've been through this steps quite often, until I decided to change my strategy. Sharing a bit of my point of view on the theme, I particularly prefer to work on game projects alone, especially for game jams and prototypes. Working on a team takes a lot of your time if you are the head developer (managing people take time). I figured that it would usually take me 50-60% of my productive time just to manage and lead the team.

The other aspect I changed was to highly reduce the amount of assets that I do myself. I prefer to use free assets or buy bundles to quickly get a cool visual. I tend to get motivated and inspired as the game looks like a game, then I tend to have a nice looking prototype very soon.

Finally, for the knowledge part there is no other way than just studying and practicing over and over. I'm very familiar with Unity after working with it for about 8 years, then I can get my way around very well (I think). I like to try new tools, but I would not do it for a project like that. You see, I try to separate my projects (things I want to look and work nice) from my studies (things I want to experiment, regardless of the look).

In any case, making games is NOT easy at all, but it can be more "streamlined" if you figure what tools and strategies work better for you :)