I'm not a developer, but my work is quite close to research and development, including programming, so I understand your situation. Delaying deadlines and making adjustments is a completely normal development process; you don't need to beat yourself up over delays and changes.
Please try to remind yourself that you're always making your creation better, even if it means making mistakes, so your decision will always be the right one. No one in their right mind would dare accuse you of shifting the estimated update dates.
After all, even AAA developers manage to push back releases and updates by months and years.
I wish you strength, mental well-being, and successful development. Don't forget to rest!