pyometra

Hello my female dog is ~12 days into her second heat. she is 1,5 years old, medium sized mix, not spayed. on saturday (8 days into heat) i fingered her for the first time. i cut my nails, used a nail file to remove spiky parts and thoroughly washed my hands beforehand. After not even 5 minutes...

(New to all of this) My question is, is there like a rule of thumb for dog breeds that are less likely to get Pyometra as Ive read that overbreed breeds are weaker immune system?

I have some questions about females. Pyometra is fatal and it can be treatable with OSS and spaying, but I heard that it's not good to operate an OSS because with missing womb the vulva/pussy will maybe shrink and a male dog or a human could break the operation seal at end of the vulva/pussy...