Skip multi-factor authentication IP whitelist

I don't think that this is right. According to the document linked above ...

https://docs.microsoft.com/en-us/azure/active-directory/reports-monitoring/quickstart-configure-named-locations

you can create a named location with 1200 ip ranges, and then mark it as trusted. Then you can use this in an exclude on a CA policy that mandates the use of MFA.

All that said, if you have AAD P2 the AzureAD Identity Protection feature is better, it learns the patterns of users and determines login risk, use it to only requireMFA when the risk is medium or above and your users will be unlikely to eer see a prompt, but rogue login attempt will be thwarted.