Keyboard mapping in Chrome app

I am controlling a MacBook using a Chromebook via the TeamViewer Chrome app. (My only other option on Chromebook is to use the Android app, which is built for mobile devices and does not work well on Chromebook - for example, it's not possible to scroll using the trackpad.) The TeamViewer Chrome app's keyboard mappings are not intuitive (Everything->CMD, ctrl->ctrl, alt->option), and I do not see any way to change them in TeamViewer. Additionally, the Everything button is unreliable as CMD because it also triggers the Everything menu on my Chromebook. Sometimes, using the Everything button even breaks the keyboard mapping in TeamViewer (Mac suddenly seems to think I'm holding down CMD and Shift) until I disconnect and re-connect. I've tried to switch the modifier keys using Mac's built-in Keyboard settings or the third-party Karabiner app, but it is unsuccessful. (I've done this successfully using built-in or external keyboards, but it doesn't seem to work with the TeamViewer Chrome app; TeamViewer's key mappings don't change regardless of these settings.) Is there anything else I can try? Otherwise, the Chromebook-to-Mac remote control is unfortunately functionally unusable, due to the issues described above. Thank you!