Being frustrated is nothing new to banjo players. If you just got your first banjo, you will see that even your years of experience on other instruments won't give your right hand that much of a head start on becoming *fluent* in Scruggs-style. It's like a language where a great deal has to be committed to muscle memory where it can then be called on almost effortlessly. This effort takes all but *extremely* talented musicians several months at the least.
If you've fingerpicked the guitar, you'll see that to a degree, that actually creates an additional obstacle, which is over-reliance on guitar-type patterns when you should be switching to Scruggs patterns in your brain. The thumb works entirely differently in the two styles, where in Scruggs the thumb's biggest job is to get most of the melody, even on the 2nd string at times, with an occasional hit of the 5th string.
Sorry for all the "bad news" above, but with 40 years of banjo teaching so far, I am confident I am telling you right. I know it's disappointing for an experienced musician to hear this, but I am trying to help you have realistic expectations.
I will recommend to you my DVD Beginning Bluegrass Banjo, which will present all the main elements of the style, slowly, and help you integrate the elements a step at a time. That will get you playing a number of relatively *easy* pieces, and the more you work on them, the easier they will actually become. Be sure to adamantly resist falling into guitar patterns that "sort of" work, but are not real Scruggs style.
When you feel ready to tackle FMB and DB, you can then use the Play Along Banjo CD/booklet that I did for Music Minus One years ago. Both pieces are played at typical fast speeds (164 and ~140, I think, about 11 and 9 notes per second respectively) on the CD, and the main breaks for each are tabbed accurately in the booklet. You could start by just learning the tabs, with reference to the recording, and if you can reach those speeds, playing along with the record, with me removed from the sound by way of your stereo balance control.
There is no short cut to being able to do this, unless you think of focused practice as a "short cut".
If you want to do it strongly enough, you will do it. But don't underestimate the effort, as many do.
The very best of success in your quest!