Youtube channels still have RSS buried deep, deep within them. The downside is, it's a bit obtuse to get the feed URL. Youtube wants you to use
What you want is https://www.youtube.com/feeds/videos.xml?channel_id=UCDRmGMSgrtZkOsh_NQl4_xw where that big string at the end is the "browseid" of the channel you're looking at. You can open up the youtube video in the inspector and ctrl+f for "browseid" to get the value, but that takes time and sucks if you have dozens of channels to do.
A while back I made a really nasty linux one liner to spit out the full RSS url for me. One would change the youtube URL at the beginning to the channel of choice.
curl https://www.youtube.com/c/SecretBaseSBN | grep -oE ".{0,10}@id.{0,100}" | perl -pe 's|.*\.com\\\/channel\\\/(.*?)\".*|\1|' | echo "https://www.youtube.com/feeds/videos.xml?channel_id=$(</dev/stdin)"
That of course requires having access to something running linux with perl installed, which may be a big ask depending on how much of a dork you are.
I did a quick online search to see if someone had made this a webpage, it was mostly guides and the one site that said it would do this gave me a feed, but wouldn't give me the feed URL without an account.
If you have a LOT of subscriptions, like 100+, you'll probably want to start by exporting those from your account. Freetube has a guide for doing so which will give you a CSV that contains the browseid/channelid mentioned above (plus some extra data), that you can then turn into RSS feed URLs however you see fit.
Sorry for all the words, I thought I made a post about this before but I couldn't find it if I did. I love having Youtube fed to me in an RSS reader. I only get the video titles, no thumbnails or extra crap. But it can be a real pain to get set up if you don't know where to look. And I do not wish to subjugate people to modern web search to find those answers if I can avoid it.