if it is any consolation the guitar is much easier than the violin,and [imo]easier than the English concertina.
try specific exercises for improving flat picking]play triplets in the following combination, dud dud then dud udu,then ddu ddu and for pattern finger picking try 5 321 4 [0r6] 321,5 312 4 312, 5 123 6 123,
then try just practising thumb altenating between 54 64 56 46,when you have mastered tha ttry a pattern based on alternating thumb for every beat with half beats in between 5342 5341 6342 5341,practise this on open strings first then change the pattern, so that on the first beat you pinch two notes together[53]crotchet 4 then 2.rhythym crotchet two quavers.Dick Miles