Rhubarb no natural pectin to speak of, so adding it is totally required for jam or jelly. A recipe for regular jelly of pectin-rich fruit like apple or grape will simply not work for rhubarb. (I can't speak about no-cook recipes, which I have never used.) Definitely follow a recipe for something like strawberry or peach jelly, but adjust sugar to taste and have extra pectin on hand: the high acid content of rhubarb may break down the gel faster than other fruit juices do.

I've sometimes wondered if a pinch of baking soda at the fruit boiling step would neutralize enough of the acid to mitigate the problem of non-gelling due to acid; haven't tested the idea yet. I wouldn't add it at the jelly-boiling stage because the fine bubbles from the acid-soda reaction will spoil the clear effect of jelly.

I've been told that the no-gel due to acid problem also happens when making pineapple jelly from fresh fruit, but not when using canned because the heat of processing has broken down some of the acid. Heat also breaks down pectin over time, so don't count on boiling the jelly to solve the acid problem. It's a balancing act.

If the jelly hasn't gelled in 8-10 minutes of rapid boiling, in all likelihood you need more pectin. Add the whole new amount according to package & recipe directions. Don't try to use a bit extra at a time to see if it gels before adding more: The first addition will be broken down by the time the 2nd addition has boiled long enough to gel. Bear in mind, too, that a certain amount of sugar is needed in proportion to a certain amount of pectin to make it gel, so if you like your jelly on the tart side, be careful how far down that road you go. Another balancing act.

I wish I understood the biochemistry behind it all!