You can delete your account and everything in it at any time. There are two ways.
Deletion happens immediately and you are signed out.
If you can't reach the app, email usestashly.app@gmail.com from the address you signed up with, asking for your account to be deleted. Requests are handled within 30 days.
Everything, permanently:
Nothing is kept after deletion and nothing can be restored, so export or note down anything you want to keep first. Routine server backups are overwritten on a rolling 7-day cycle.
To remove a single item rather than your whole account, swipe that save in the app and tap Delete, or long-press it and choose Delete.