I have been doing competitive programming for the last 4 years. But after the initial 2 years, I feel like I haven't made any progress. Whatever new topics I learn, however much I practice and participate in contests, there's always a limit beyond which I can't go. Even though my max rank is Candidate Master in my original account, I still can't solve beyond Div2-D problems (very few of which I actually solve at contest time). Lately, I'm very demotivated and can't even solve problems that I previously solved myself. This is making me wonder if I have really wasted a significant portion of my life in front of a screen doing something pointless. I usually find it very difficult to give up on anything I'm pursuing and I'm particularly scared of giving up on competitive programming because I've spent most of my college years doing this and it's all I have to show for my skills.

Can anyone provide me with any good suggestions as to how I can get back on track or push myself beyond this threshold? Or should I just work up the courage and give up on this?