My first step was to find another service like MailChimp. After a little searching, I decided to try out Sendinblue (https://www.sendinblue.com/). However, the email it sent out was not impressive (I selected a RSS publish, and it did not show any links except to the main posts), and the subscription form had some problems in sizing, so I resumed my search.
My next experiment was to look at the mailing list feature provided by my web hosting service (based on GNU Mailman (https://list.org/)). I spent about 4 hours over 2 days poring through setup instructions and managed to get a mailing list set up that seemed to work the way I wanted. I then needed to create a signup form, and tried using WPForms (https://wpforms.com/), which was available as a free plugin within my WordPress install. I got a form set up, but then had problems getting the form to send an email to the email address for the mailing list to add a new subscriber. At that point, I decided to try another tack – looking for a WordPress plugin that could handle everything.
The first plugin I tried was WP-Subscribe (https://wordpress.org/plugins/wp-subscribe/), but it only worked with MailChimp, Aweber, and Feedburner (could not use any other email delivery provider, I was thinking I could reuse the Mailman list I set up, but no go). The grand prize winner was The Newsletter Plugin (https://www.thenewsletterplugin.com/), which had a free version that supported signing up subscribers, creating a newsletter, and sending it out to the list. After about an hour of testing, I sent out my first newsletter, and it looked good! I ended up deciding to copy the text from the daily weblog post to the HTML email newsletter form, and adding custom embed code for Twitter posts.
Overall, I learned a lot about setting up mailing lists and figuring out what I wanted from a mailing list tool. My top features were price and ease of use. If I could have created another MailChimp list, I would have done it in a second (since I had an account). Since I did not want to spend anything just yet on a new mailing list provider, ease of use was the next criteria. It was a shame that it took the better part of two days to weed through the contenders, but I think I found a solution that will at least get me started.