I’m unclear with your post as to why your deadlocks are considered unsuitable, but here’s my experience:
I had a double deadlock installed when I first moved in; the deadlock was fine for many years but then got hard to close from outside without slamming hard enough to bring the building down, so I called a locksmith to replace it, which he did.
I immediately noticed a difference: old lock – it’s double locked and coming in carrying a load of stuff I inadvertently left the keys in the lock outside, and the door slams closed behind. Keys outside; me inside, door locked. I had to hunt around to find my spare keys to unlock door and get keys from outside, so all okay.
The new lock, same situation BUT this time: unlocking the door from the outside also un-deadlocks the lock from the inside, so no need to find spares, just open door and retrieve keys. It’s still locked from the outside, but not inside. The locksmith said that was how the newer deadlocks worked to avoid people locking themselves in.
Sometime along the way, I decided the best place to keep my keys when home, was, in the lock inside, which also allowed me to keep it deadlocked, but no delay finding keys if someone shouts “fire”. The only time I lose my keys now is if I don’t put them straight into the lock when stepping in.
Maybe that is applicable in this situation?