avoiding using primary domain to avoid blacklisting, do not send more then 50 emails a day from one email address, allow email warming to improve deliverability, use Google domains etc., with that in mind what allows services like Mailchimp, Klaviyo, HubSpot and of course Accumail avoid these rules and allows them to send marketing emails to 20k addresses a month without all these concerns or do the same rules apply? I need to determine if this is essential for my toolbox, as It will save me the need to have to use HubSpot for my startup at this early stage, thanks in advance