It seems like there is a lot of capacity for data, since your Gmail emails are not stored on your computer or phone.
The storage capacity of your Gmail account is not always unlimited.
It is a good idea to empty your account's trash if you are running out of space in Gmail. It's not hard to do. This is how.
This is the first thing. You can open your email account on a computer.
There are two Click on the word "Trash" on the left-hand menu.
There are three. Click on the message and hit "Delete forever" to remove it.
Go to the top of the screen and select "Empty Trash now"
This is the first thing. On your phone, open Gmail.
There are two The lines should be tapped at the top left.
There are three. Pick "Empty Trash Now" or "Empty Bin now" when you tap "Trash"
If you want to keep an email in your inbox, you need to send it back to your inbox before the 30 day period is up.