If you temporarily rename your untitled folder to have a . in front of it ( so .untitled ) are you able to load into the game? (This just tells SMAPI to ignore that folder, so it will load up Stardew Valley with only the basic mods that weren't in that folder.
If so, that seems like it's an issue either with a specific mod, or possibly just the number of them. What's the longest you've waited to see if your game will load, before closing it out? My specs aren't awesome, so if I have a lot of mods installed, my computer will helpfully tell me it's not responding but it will load eventually.