Kitty does this as well. They have a section on ssh-integration on the wiki. I personally love it. I can use the kitty multiplexer remotely and I can copy and paste from local to remote. So at least he does implement a solution/alternative.

The thing I like about tmux and zellij is persistence and the "task-runner" nature of them. Its great for managing sessions and running things in the background. Though I do hate how they also break a lot of features that I do like about terminals.