I also have a TM3 from 2019 with an Android phone (OnePlus 7T Pro with Android 11).
Roughly one out of ten times, I have the same problem as you. I start the app in order to pre-heat the cabin from distance and the car just won't wake up which is a prerequisite for this function to work.
During the last two years, these step-by-step work-arounds have worked for me in the following order:
1. Close Tesla app, and restart it.
2. If 1. doesn't work, close all other apps (via built-in Task/App manager) and restart the Tesla app.
3. If 2. doesn't work, go to smartphone settings, Apps, choose Tesla app, go to storage and clear cache (not data !). Restart Tesla App.
4. If 3. doesn't work, take your smartphone and go next to your car (distance +- 1m) and retry.
5. If 4. doesn't work, unlock your car with either key card or Tesla App (no LTE connection required for this), take a seat on driver seat and retry.
6. If 5. doesn't work, Log-off and Log-on with your Tesla credentials within Tesla app. Retry.
7. If 6. doesn't work, repeat step 3. but this time clear "Data" as well. You will have to re-enter your Tesla credentials again in the Tesla app like in step 6.
If all of this is still no good, then I reckon it's time for a SC appointment. Fortunately I didn't have to do so yet.
Hope this helps.