When using Team Mobile chat in DeX, there is no option using the mouse for thumbs up.
Mobile app in DeX mode could benefit from mouse options for emotes like thumbs up or smiley. Also Once the app loads under DeX the UI could be better received if it looked like and acted like the windows desktop client. I dont know if this is possible but the look and feel of the modern app in DeX works...and i know its early but could definitely look closer to the Desktop version.
Thanks...feel free to reach out in Teams :)