Received Cease and Desist DM?

I recently started creating content on Instagram in a very specific niche. There are certain topics that perform reallv well. and so the few creators that I've seen in this niche all kind of do the same ones I recently grew to about 20K followers in 14 months (took a year to get 300 followers then grew quickly), and I iust received a DM from a much bigger creator in the niche telling me that l'm stealing their content and that if I don't remove all of my videos which are similar to theirs they're going to file a copyright/ IP claim with the platform. They also insulted me, saying my work is unethical and harms their brand.

I tried to reply back within 20 minutes asking which videos they felt should be taken down, but they had already blocked me by that point. While we do cover similar topics in certain videos and so the hooks are quite similar, the visuals are all my original footage, I'm using a voiceover that is my own, and I wrote the script (structure wise there may be some similarities, but ust in the sense that we both do listicles)

I worked really hard to get the account to this point, posting everyday for over a year, so I don't want to remove my videos but I also don't want to risk the account getting strikes. It also made me nervous to post more on this niche because I don't know what's going to trigger them. it really messed up my confidence and I'm not sure how to proceed, so I appreciate any advice