If Substack is perfect for your needs then use that. Your problem with substack prolly isn't who else uses it, but rather, that you yourself are calling a proprietary, privacy disrespecting deprecated monolithic silo a "Perfect solution".
Instead of doing what's right, and for the right reasons, you eschew dogfooding on #FOSS when you should be championing it, and call a professional data mining haven perfect, when it is anything but.
Well, you're already on the Fediverse, so you should know better, but I'll dispense with the lecture now and point out a few good FOSS solutions that are Fediverse powered (and one that isn't, but still rocks as a publishing platform) for you:
Option #1, #WriteFreely, which you can find over at its git repo under https://gitHub.com/writefreely/writefreely.
Option #2, deploy yourself a #WordPress site, Then install the #ActivityPub plugin - the latest release publishes into the Fediverse and allows any Fediverse account to reply/comment threads natively - like I'm responding now. It also allows anyone on the Internet to join the discussions as well. WordPress has many options for subscriber lists, Etc., as well as #paywalled#digital_downloads, if you like.
Option #3, #Mitra is a Fediverse publishing platform that currently supports paid subscriptions for Authors: https://mitra.fediverse.observer/list - pick one that has open registrations or self-host yourself, like all of the other solutions here :)
If you're really talking about maintaining subscribers lists, but especially Having a subscriber list and building it up, then most ignorant folks would recommend HubSpot - but they would be wrong, because you can get the same powerful inbound marketing solution / #CRM, only better, for #FREE (That's a bare minimum savings of over $500/month)!!! So install #Mautic and let it do what it does, which you can get here: https://www.mautic.org/download/source-code and then after that, use it in conjunction with the following FOSS application that was tailor made for exactly what you're asking for...
#Ghost is FOSS, and in conjunction with an inbound marketing platform like Mautic is the perfect dynamic duo - like Batman and Robin. But even better, is that I'm going to point you towards a #HowTo that is an actual cookbook #tutorial written by someone expressing the same lamentations as yourself, and here's the exact solution they've provided for you:
By the way, your Mautic server also integrates directly with#MailGun (or Sendgrid, SendinBlue, SparkPost, etc.) to complete your transactional email system that will tell you when each and every recipient received, viewed (and or how long) your emails, as well as how many times they looked at those emails, with a bunch of other tools as well.
I hope that helps, and I'm very glad that you came to your senses about not using a privacy disrespecting, proprietary closed source solution like Substack - besides, registering your own domain name would have hidden the fact that you were using substack anyway, so it's about YOU doing the right thing the right way. Please choose your software in the future based upon the freedoms and ethics it offers in serving you and your customers. There's evil people everywhere, and the smart ones are using FOSS too - not substack.
