[latexr]

Those are a dime a dozen, and a web search returns multiple on the first page. They tend to be submitted to HN. Examples:

* https://blogtrottr.com

* https://feedrabbit.com

* https://feedsub.com

[Ruthalas]

Blogtrottr had been working for me for a half dozen years, no fuss.

It's monitized by an ad at the top and bottom of each email.

It also provides an option to send an initial email with the full history of the feed to date.

No affiliation, I just happen to use it.