Help I'm stuck on the World making screen!

Sweet Jesus, 45!? 

I would start by testing each mod one at a time until you find the culprit. I'm no technician though, so that's all I got for ya. 

if the world is not generating and you are using a mod that is altering the world generation, then it is for sure (one of) this mod/s.

A logfile would help alot to find out the reason.
And then report this issue not here, but to the modpage, so the auhor can fix it.

Most likey it is the "Do your map" mod (just guessing because this is new an can make islands)? The description there already says that this mod is in beta and may cause problems, in addition the mod allows you to set impossible settings, so even after that mod is completely finished, depending on your settings this can still happen.

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you can also use my teleportato mod, together with my "Increase Animals and Setpieces" which already exist since several years and do allow most of the customization without problems, including islands.
https://steamcommunity.com/sharedfiles/filedetails/?id=756229217

Edited September 20, 2020 by Serpens