Ask HN: Mailchimp is shutting down TinyLetter. Alternatives?

I'm a happy TinyLetter user and would love to not add another monthly subscription cost, especially since the rest of my website stack is free. I fit in TinyLetter's < 5k subscribers free tier.

I checked out Buttondown and Mailchimp, both of which require paid plans long before 5k. I worry self-hosting would hit spam. Any good alternatives?