Step 1: Go to the App Settings from Homepage of the app.
Step 2: In App Settings page, click on Account & Security card. Then the Account Control page will open.
Step 3: Now, from Account Control page, under Danger Zone, click Delete Account.
Step 4: After clicking 'Delete Account', a bottom sheet will open. Type "DELETE" on the input field. and click the Delete Account button. After a few seconds, your account will be deleted and you will be logged out of the app.
You are done. All your data will be deleted instantly.
If any question,
Ask on mail@proton.me [Shakhawat Hossain, developer]. Also, make sure you include the app name "SelfThrive" in the email subject.