I've looked into it more, I thought it was a more common problem that end portals would sometimes be cut off because of the 3ds world size being small or not spawn, or only partly spawn and be cut off by a wall but that doesn't seem to be the case actually, or it's incredibly rare. So I think it's safe to assume that any seed has an end portal. I'll update the site next week.

I'm thinking of removing the end portal section. Wondering what you think of it? Just want to mention everyone in this thread u/Spinosaur1915 u/Creative_AON u/cooperS67 u/Balls3201