One way to create a RSS feed is to export all your existing subscriptions directly from your youtube account. Go to your Account => Notifications => Manage subscriptions. You should find a button to export all subscriptions as an OPML file. You can then import that file in your favorite RSS reader (I use Thunderbird for that and works just fine).
[UPDATE: 2022-03-21:] The OPML file is no longer available from the acount section but I wrote down some alternative here.
You can also add individual channels to your RSS reader by using the following URL:
https://www.youtube.com/feeds/videos.xml?channel_id=CHANNEL-ID
replacing CHANNEL-ID with the actual ID which is a 24 digit code starting with UC. It is sometimes hard to find as you can enter the channel via the user name but you can find it in the HTML source code of the channel.
Of course it is still good to subscribe to your favorite channels in your youtube account to support the creator, but I also find it more convenient to let my RSS client check for updates instead of checking the web page manually. BTW, I don't like the bell notification as I don't want instant notifications whenever someone uploads a video or post some message. I prefer to just check for new content whenever I take the time for it.