Hi, my advice would be, dont worry. In fact picking one with better developers in will only benefit you as they will provide comments and feedback on your entry. I am hosting a jam this month for all levels and will be playing every game submitted on my youtube channel where I'll be offering tips and feedback on how to improve. https://itch.io/jam/xanderjam-1
Viewing post in Finding a Game Jam?
I see two options. You could go for a longer game jam. There are some month long ones. opengameart.org does some. https://itch.io/jam/fall-all-oga-game-jam-2020 is ending this month. The other option is to create an entry for a game jam but don't enter it into the game jam. If you game jam is 6 days and you don't have something playable, keep working. If on the 14th day your game is done, upload it and maybe mention it on the game jam forum. You probably won't get as many people trying your game but maybe the experience will help and allow you to meet a time limit in the future.