I don’t know what most do, but I certainly prefer the default Mail.app over the vendor-specific mail apps.
If you’re already using one of the major providers (GMail, Outlook365, etc.), there isn’t much to configure; you go to Mail Accounts, click your provider like Google or Microsoft, and login on their website to authenticate.
Oh for sure. Huge assumption on my part. I just feel like 90% of people I work and interact with have a gmail account, and the last 5 companies I've worked at used gmail. I think the last time I setup Apple Mail was for my Grandma so she could see her old Cox account emails and Gmail emails in the same app.