The only difference between the Safe 3 and 5 are the physical buttons?
Discussion
And two digits greater number in the name, one for each of the buttons. Apple only ever dared to add one digit for the previous year’s identical model. Trezor really innovated here.
Safe 5 has touchscreen, so typing passphrases and pins is possible and practical on the device.
Also the shamir backup by default is on 5 I think, but you can always choose shamir backup on 3 and T manually.
Safe 5 also has haptic feedback.
Also firmware has much better UI/UX. Nice animations, ...