I see, not sure how far you're willing to pursue this but you _might_ find help on Reddit or Discord. I would be very surprised if you are the first person with short thumbs to want a Dactyl. Someone might have paved the way with a hand similar to yours.
Some subreddits that I know: r/ErgoMechKeyboards r/MechanicalKeyboards r/olkb
Also I know about these on Discord: SliceMK KBDFans BastardKB SplitKB QMK