Since you are using an SSH connection to connect with your workstation, ensure that the network that you are using has low latency.
You could also try to compress all your data to improve the functionality over a slow network by using the "-C" flag.
ssh -X -C % https://explainshell.com/explain?cmd=ssh+-X+-C+user%40host
This laggish behavior could also be a result of X11 security extension controls and to bypass these controls, you could replace the "-X" flag in your command with the "-Y" flag. Although this leads to a less secure session, it should improve the performance of MATLAB on your remote desktop.
ssh -Y -C % https://explainshell.com/explain?cmd=ssh+-Y+-C+user%40host
I am unsure about the root cause behind this issue but as a rule of thumb, GUI applications are bound to be laggish when working on them with an SSH connection that uses a modem or a high latency network. Personally I would suggest using VNC or X2Go for remote desktop access over using X11 configuration with ssh.
To read more about the "-X" and "-Y" flags you can check out this discussion: https://unix.stackexchange.com/questions/619083/ssh-is-better-to-use-x-or-y
