+1 for sending newsletters to Feedbin. It’s a great feature.
The only issue I had once was a newsletter provider who required you to reply to an email to confirm you wanted to subscribe (which of course you can’t do as it’s only for incoming emails), but I contacted the newsletter owner and was approved manually.
HOLY CRAP I have been wanting this exact feature for years. I always thought why aren't Newsletter and RSS reside in the same space. I rarely use email anymore given all the spam and advert.
https://kill-the-newsletter.com/
https://github.com/leafac/kill-the-newsletter