Again, nobody other than you have said tekki shodan was meant for ground fighting.
since the beginning of karate, Bunkai has has different "groups". Literal, Hidden, and True.
The most basic movement in any for is block to the down and punch.
When teaching a new student, that's how we explain it.
But it's actually a takedown And zero changes need to be made.
Earlier I gave an example of how a punch/block into a hidden fist chamber was in the beginning of Pinan odan.
Again, to those learning the form, that's the movement.
But it's a gi choke, again with no change in technique. The punch/block lines your hands up perfectly to grab the collar.