As long as you use the same username/email and password, yes, you can. But performance can vary from person to person. I've had some issues with the official client, and haven't had any issues with the Steam client. For other people it's the reverse.

If you have stuttering on either client, you can edit the engine.ini file for better optimization. It doesn't seem to help everyone but for me, at least, it removes most stuttering: https://www.reddit.com/r/TowerofFantasy/comments/wpaozv/ue4_engine_tweaks_guide_to_improving_graphics_and/

Also, if you're using an Nvidia card, you can replace the DLSS file with the latest one, which should also help: https://www.techpowerup.com/download/nvidia-dlss-dll/

For Steam, the DLSS file is located in C:\Users\your username\AppData\Local\Hotta\Saved_Steam\Config\WindowsNoEditor

There are two files with very similar names. The one you want to replace is: nvngx_dlss.dll