I used to read RSS feeds from Thunderbird a long time ago, but that required me to set them up again on every reinstallation and every device, so I eventually stopped doing that.

Nowadays I read RSS feeds on Mastodon. There’s a service https://rss-parrot.net/ that converts any RSS feed into a fediverse account, so you get RSS feed updates into your feed along with everything else you follow there. Of course it would be even better if blogs and news sites just posted directly on the fediverse, but not all of them do.