Counting non-subs and unsubs is a dick move by Mailchimp. They have been losing ground to the competition and this will just accelerates that trend.

As for competitors, add Active Campaign, IContact, Mailer Lite and Twilio SendGrid to your list. AWS SES is a much simpler type of service but it also costs a fraction to use. You can use something like Sendy.co [0] as a service on top of SES if you don't want to mess around with the horror show that is AWS.

[0] Sendy alternatives: https://geekflare.com/aws-ses-powered-email-marketing/