career advice:technology switching or M.tech?

I have worked in an IT company on as/400 development for 1.5 yrs , then i took a gap of 2 years to crack GATE i could not make into IITs( AIR 8000 )I have done B.E ECE (2012 passout fron VTU ) now i am trying to come back to the same industry: but due to reasons
1.gap in the career
2. .... and only few companies( IBM, Galaxe . 2 or 3 ...) are hiring resources for as/400 synon development ( as/400 is mainframe technlogy , Synon is a tool used )
I am finding it very difficult to get job its been 1 year am trying ,

I need the advice from you guys on this ,
1. should i switch the technology?
if yes : which one is better or having more job opportunities , like: .NET , or JAVA or big data .... or etc?
2.should i stay back in the same technology i.e AS/400 synon?
but here am trying to find jobs from one year , am refreshing my skills , but no interview calls yet ,
3. should i join state universities for M.tech ?
which electronics courses are good in karnataka ?

all your opinions are valuable for me , please throw some light on this .
thanks in advance to everybody 😀