I had a (freakishly) similar background to you, I completed my training and did a basic, but highly recommended, MCC then spent a good part of a year with no luck with recruitment. The only "bite" I had was attending selection with a large northern low-cost operator, where I got through all the stages but ultimately they turned me down on the basis of soft skills/horrible personality.
I took the plunge and did the Wings Alliance APS-MCC course and now I'm gainfully employed to operate an Airbus.
I chose to effectively repeat the MCC for several reasons: I wasn't getting any younger, skill atrophy in the job hunting period, my highlighted soft skill deficiency (soft skills taught at the forefront throughout the WA course), the past success of WA graduates and the post course career support offered. It also appealed as I had attended Bristol Groundschool for my ATPLs and I had seen the genesis of the project and noted that this was not a sausage factory motivated by short-term profits. They were absolutely pivotal in me getting my current job and I had two more selection days with other operators lined up as alternatives when I accepted my current position.
If I had to do it all again and knowing what I do now, I would go straight through WA and not touch the other courses. In my view the first MCC was a waste of time and money and really not relevant to my current job; it was essentially an FNPT2 with jet noises with someone else to operate the flaps/gear - nothing more than that required to tick the boxes, but at the time I did think it was great! On the other hand the WA course really was a natural progression from Duchess pilot to the start of a multi crew type rating with soft skills development and career opportunity support.