iATKOS | United Kingdom

I'm on latest Catalina build but cannot download big sur from the App Store as it says it's can't find a release no matter what I try or google I can't seem to get the release version.. so I am using gibMacOS from Catalina to make an install disk but it keeps failing to download and get's stuck at 99.88 approx percent, it's also incredibly slow. is this normal as I have done this 5 times only for it to fail. any other way of downloading big sur install so I can use it with open core