...I don’t plan on riding in bad weather, but I won’t be able to avoid it if I head for the Stelvio Pass in 2022.
I wouldn't worry about the rain on the Stelvio. In summer on the Alps it is easy to find a downpour, but they don't last long. Usually as soon as you have finished wearing the rain gear the clouds move away and the sun shines.
However, I hope that the tortoise will reach you by '22...