Calling on all thanksgiving cactus experts AND crown of thorns experts!

I have these two planted together (as was given to me) - would it be better to repot & separate them? The soil is not greatest, I think there is some sand in it. But they do look good.

What do you think? Is it too late?

If repotting, what is the best mix for each of them (I would think gritty, but would like to know for sure).

CT is quite tall, it grew some in past few months.

Thnx. Rina