While it does suck that everything was cancelled everyone else who has these ECs are also going to be in the same situation. I think you could use this as a time to show great leadership skills and why you're the co-captain of MUN/Mock Trial. I'd worry less about winning awards (since no one will be getting them) and more about how can you use this time to show colleges you are an effective leader and determined to still put together the best MUN/Mock trial team you can.
What did your team do when there were events? I'm assuming you had meetings/practice. Is there a reason this can't be done over Zoom or something similar now? What schools did you typically compete against? I'd reach out and see if you can get enough groups interested in doing virtual debates/MUN. Consider them "friendly" matches like something they would do in soccer. If you were able to organize an event with multiple teams and still lead your school's teams through all of this I think it would teach you a lot and give you some good things to talk about on your applications. While you might not be able to compete this year, what you practice and learn will still be useful for next year and beyond.
You can look at scheduling non school sponsored practices as zoom has a free version gmail/google has another zoom like thing iirc called meetings and you can schedule a time to talk/ do something virtual.
Also I compete in debate and as it is uncertain talk about what you were slated to do. I was slated to compete in national qualifiers for debate but I can just say I qualified to compete at nat equals and state. Instead of not talking about big competitions otherwise.
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Also you can do some semi silly stuff like superlatives essentially depending on how big the team is you can organize it as a leadership thing.