I only diverged from these videos in two ways: used Sonoff-Tasmota v5.14.0 since the wireless wasn’t working with the version mention in the video and I had to manually enter the Sonoff’s IP addresses to Sonoff Connect since they were not being discovered.
ST doesn’t provide a GUI option to toggle it as a switch and Simplify doesn’t load them either.
I flashed them with sonoff.bin and not sonoff-allsensors. Do I need to configure them to work as sensors or switch somewhere in the Sonoff-Tasmota web interface?
When I previously flashed it with sonoff-tasmota the green light would flash when power was applied and I could access it’s web interface, just couldn’t get it to work with ST. Now it’s just dead with no lights and no WIFI even though NodeMCU flasher loaded the flash.
I have flashed a bunch of these, some had the same results as you with no green light, usually I just reflash with a different tool (ESPFlashDownloadTool_v3.6.4) and they seem to work after. I have over 20 of these and they have been pretty solid.
The DTH might need to be updated for the new ST app (I refuse to touch that garbage app until Samsung forces me to ).
Out of curiosity, did you backlog your settings to your Sonoff or set it up through WiFiManager? Also, did you setup a username and password for your Sonoff? On all of mine, I don’t have a user/pass and I set mine up through backlogging in Termite. You might need to go into the web console and tweak things around a bit. I had to make sure that for all my Basics, GPIO14 was set to 09 Switch1.
I have the same problem: after flashing and WIFI connection it works with the Smartthings Classic app but keeps with “Checking status…” and “Can’t connect to device” with the new app.