I hope this finds you well! I just saw your post and I see myself as a little bit of a tech nerd but not sure if you've found what you are looking for yet.
There are so so so many different apps out there for mental health - it might be a good idea to clarify what it is you are looking for. Something to track your moods? Something to use as journalling? Ones for meditation? Suicide planning?
I have a couple that I use for keeping safe and panic-mode, but for general mental health I use MoodNotes as a way to journal and check my thoughts to see if I'm falling into any thinking traps, Worry Watch - as a way to write down my worries and basically see if they come true or not, and SuperBetter. The SuperBetter one is a little hard to explain, but basically it's gamified mental health - so things like practicing gratitude and drinking water is a power up, and talking to my inner self-critic is a bad guy. It's good fun :)
I hope this helps!