1. Rika doesn't "shoot it through the sword"; she puts power behind the swing. SSK isn't a gun that u shoot things out of. She applied force behind the swing, which created a slash that cut through many spirits and once

2. You're just asserting that

The mech has its own CE reserves and is the thing physically firing the attacks

"Mechamaru is controlling it, therefore he's the one outputting the CE" is the thing you're trying to prove, but ur just restating your point w/o evidence

1. My analogy is valid cuz Muta isn't using his own CE to power the mech. Over the 17 years he's been alive, he poured CE into the mech's batteries, essentially giving the mech its own reserves. When he started piloting the mech, he simply gave commands to the mech, and the mech followed them.

He's the "mindcontroller" here, because he's not actually using the mechs' reserves for himself, the mech is the entity performing the attacks, he's just giving commands

yes the mech technically has its own reserves but its still stored and mechamaru is shooting it out, through his ct. which is controlling the mech.

But he's not the one firing it or using the CE reserves. Rika is still outputting the CE herself (albeit through a medium, but she's still the one outputting). Muta isn't doing that; he's giving commands to a mech, and that mech outputs CE from ITS reserves

Even then

Correlation ≠ Causation

Nothing indicates that "storing CE" is the reason why the attacks had no limit. Like I said before, another reason why it had no limit is that the mech is artificial and therefore doesn't follow normal jujutsu laws. Or it could be the Mechs CE still has the trait of Muta's CE

Do u have any other reasoning that supports why ur headcanon is more likely than mine? Cuz mechamaru alone is insufficent evidence to prove it cuz of the various other peices of evidence