With all due consideration,
The Pali sam-, san- preffix is the equivalent of the English com-, con-.
ManySince samsara is the opposite of nibbana, which is the unconditioned, the most accurate term for qualifying both samsara and sankhara would be conditioned or conditional, pertaining to conditions. Also, many suttas explain that conditional existence samsara is the sum of all conditioned phenomena sabbe sankhara.
The conclusions that arise are graphically sketched as follows.
Respectfully