Bolt was from the M1 Garand. That came before the M1 Carbine and was the example that he saw first. Gas system was also inspired by the Garand, just flipped upside down (from the Garand’s perspective)
The magazines were possibly inspired by the Stg 43/44 I haven’t seen research on that.
Kalashnikov was a smart guy that put some working things together in a more modern way. His methods and what he did, should be taught in engineering schools.
You don’t have to re-invent the wheel. You can, however, take well working systems related to your wheel, and make the sum greater than the parts.
The Soviets had some M1 Carbines that we gave them during WWII, so it’s possible that ol’ Mikey T saw one. How do you know that he saw a Garand before he may have saw a M1 Carbine?