Trending @Cognizant; Lotus Notes competency

I was trained in Advanced Java during internship and when I joined as FTE, I was deployed in a Lotus Notes project and since then I am working as a Developer/Administrator/Support in Lotus Notes. It's not like I am not happy but I am concerned about my future as I am already having 4 YOE.

Can anyone please suggest me what I should do? I am skilled in Java, Springboot, Angular as well but since I don't have hands-on experience I don't get opportunities.