I've managed bigger projects before but something about writing a script seems difficult to organise  Also being sad and lazy doesn't help but I'm almost over that.
yes, for you i recommend doing shorter projects. and then if you are still even slightly overwhelmed, then i would still recommend even shorter projects. if you don't believe me, check out the videos i was doing during 2014 and 2015. if i could have started with something like 'history of japan' first, believe me i would have. but i was going through the exact same thing as you. building a world is a mindfuck. it can be done, but you gotta work your way up. i personally am still working my way way up, there's a long way to go still. but yeah, if you want the secret to unlocking multiple huge mountains, the answer is to start brainlessly small and simple. this trick has worked for me over and over and over and over again, and i am doing it again now as we speak