(But I use Feedly.com web site on computer and Feedly app on phone now which is easier for managing RSS than Thunderbird by a mile. Though looking below there is Export/Import of feeds, I'm not sure there's a way to just sync them up everywhere. And I don't use Thunderbird on my phone!)
https://support.mozilla.org/en-US/kb/how-subscribe-news-feed...
I’ve switched to NewsBlur a few years ago. Happy paying customer. (But bot affiliated). The bonus is synchronized phone/laptop/desktop reading status.
I have to confess: little automations like this with low barrier of entry is where I find most value in tech. Simple and practical.
You may be fine with your solution so this comment is more geared towards others who are interested in a similar solution.
I am sure managed RSS platforms also offer some kind of email digest if you don't want to self-host.
The "email digest" approach is basically DIY newsletter. While this approach works for me, it may not work well for others. YMMV.