What's wrong with gmail? I believe they are the most trusted, secured and widely used email providers. You can go for Google's paid mail service if you are not happy with their free version which most people widely use. I bet you will like their paid service, where you can bind your domain with gmail too.
People who pay for email service usually look into privacy or encryption.
Sure gmail does the job. However, you let them collect data from your mails.
I also suggest ProtonMail.