A change in ESC would effect the RX only if it's not feeding that RX enough voltage to function. Since your setup was actually a very common one, that shouldn't be the case but if it is, the issue is likely on the ESC's BEC output side.

What do you mean you had to set some sub-trim? Did you set the ESC to your TX with the TX's setting at all zero or 100 where applicable? If you set the ESC's neutral to neutral on the TX with zero trim/subtrim on the TX when doing so, you should never "need" subtrim.