Is there a macOS ssh client that allows me to type fluid commands?
As you cannot use mosh, your choices are very limited.

You can use the following perl-based wrapper for the standard OpenSSH command supplied with macOS to enable line-mode:

https://github.com/mnalis/ssh-line-mode/blob/master/sshlm

Remember to read the instructions before use:

https://github.com/mnalis/ssh-line-mode/blob/master/USAGE.txt