Any decent email service should include a 'mail collector' facility, which allows you to have mail sent to another account automatically forwarded to your new one. GMX (which I use) certainly does:
https://www.gmx.co.uk/mail/mail-collector/
If the reference to Google in your post though means that you particularly want to set up a Gmail account, and then have mail forwarded to it, you need to use the features of the
other accounts to enable such forwarding. Scroll down to 'Auto-Forwarding Emails into Your Gmail Account' here for an explanation:
https://www.besttechie.com/how-to-use-gmail-for-multiple-email-accounts/
(I still urge you to consider using GMX though; it's vastly more intuitive than Gmail is).