Good question. I used substack before and was quite okay with it.
There are a few reasons why I’m looking for an alternative. One reason is control: they can change the service in a way that I don’t like. It happened in the past with services like Medium. Another reason is privacy: it’s a US company and I’d like to have solid data protection for the subscribers. Third, I’d like to integrate the form html directly in my blog posts (without a separate page) and I’m not sure if that’s possible with Substack. Also, don’t want any branding on the page. Fourth, I want to send plaintext emails without any formatting. Basic HTML would be fine, but many platforms have these template builders, which add styling and tracking that I have little control over.
As you can see, lots of minor paper cuts and I’d be willing to compromise on most of them. However, if I need to start over, I might look for something that fits these needs as best as possible.
Thanks for the recommendation. Highly appreciated.

writen by Matthias Endler
Actually you would run into some risks like what you’re planning. So I call STOP for now.
Let me explain: You might inherit your current mail address/domain reputation. But you might also decrease it with the newsletter.
First, you should make sure that DKIM, SPF and DMARC are set correctly. And you should at least use a subdomain if not a separate domain for the mailings. Apart from that: warm-up (slowly increasing (already starting today of possible to some addresses for making the new domain known) the sending volume and slowly decreasing again) and making sure you delete bouncers fast from the list.

writen by Benedikt
Great idea to use a subdomain for it. It should technically be the same as a completely different website - at least browsers treat it this way. I will make sure to set up DKIM, SPF, and DMARC. And yes, the warmup is also a good idea.
I’ll follow your advice. Thanks!

writen by Matthias Endler
I have my own email server. Here is how I set it up: https://wannabe-entrepreneur.com/post/send-cold-emails/

writen by Tiago Ferreira
But if you have consent to send emails to all of your subscribers you can use amazon SES for example

writen by Tiago Ferreira
Running your own mail server including all the stuff mentioned above like Tiago does probably could work as the gold standard

writen by Benedikt
I think running your own mail server is 10x as hard as running a small newsletter through my company email account.

writen by Matthias Endler