So you’ve got the Aqara Wall Switch - Single (no Neutral).
The only source for a SmartThings DTH is the thread that you’ve already posted on. Based on your post it sounds as though the command being sent from SmartThings to turn on/off the switch is incorrect. The changes suggested by Kelvin_Kueh probably aren’t working for you because they were for the Dual wired switch with Neutral.
Personally, I have almost completely migrated over to the Hubitat platform from SmartThings, and from my Hubitat community thread to support the Xiaomi / Aqara device handlers I ported over, I know there’s a user by the name of @guyeeba who has developed Hubitat drivers for all the variants of the Aqara Wired Wall Switches, including the one you use.
guyeeba’s Hubitat drivers can be found on GitHub here, and although they definitely won’t work on SmartThings as-is, there might be some code in them which could be adapted for use with SmartThings.
I hope that helps!