Having trouble syncing Apple Mail and Gmail

"Having trouble" tells us nothing about what your problem is. Therefore, we have nothing to evaluate and respond to. Please detail the specific issues you are having. I suggest you click on the link below and read the information there so you can respond.

Writing an Effective Apple Support Communities Question -  Writing an effective Apple Support Commun… - Apple Community

It may just need an App Password separate from the gMail password…

https://support.google.com/mail/answer/185833?hl=en-GB

Apple Mail won't sign in to Google account - Apple Community...

Apple Mail won't sign in to Google account - Apple Community