There is a Continental USA cycling team that is comprised of diabetics that's been riding since circa 2009. I don't know whether they are type I or II, but the website lets you sign up and I assume they'll have pertinent information about both types of diabetes and how to manage it while cycling at both low levels and hard levels.

I think they started out just as Type I, however I think they now also have been demonstrating that Type II diabetics can compete. But that's up to y'all to find out.

https://www.teamnovonordisk.com/