i love it when someone tells me it can't be done
it really just adds fuel to the fire, for me.
to find another way of doing the exact same thing, and showing the end result, is better than most anything i could dream of.
i sense the force is strong in the newbie, welcome down the rabbit hole my friend.
there was times when everyone you encounter here was in a similar situation, not knowing anything about machining.
fear not, your knowledge grows in 2 ways.
first, you learn by watching/reading/listening/asking questions
second, by doing
if you were so inclined, you could reproduce the parts you wish to make with simple hand tools
a hacksaw, a triangular file, a round file, a bastard file, and a drill, is all you would need other than a work holding device.
if you wanted an excuse to buy a metal shaper, this would be the ultimate excuse.
the longitudinal grooves could easily be produced.
the forming of the concave relief could also be a rewarding experience too!
Use of a vertical or horizontal milling machine would be another way of doing the same things.
your desire will be the deciding factor
there is a will, and a couple ways