No, with coinjoins it is not enough to use tor alone, because if so, they are vulnerable to tagging attacks.
Monero is basically a coinjoin, if you don't use different tor circuits for inputs and outputs you are vulnerable.
Discussion
Tagging attack isn't a reliable method to deanonymize you since it requires all rings to be compromised which isn't likely.
It isn' "basically coinjoin" since coinjoins are centralized.
No, a network level attack has nothing to do with rings, another thing is that it is very expensive to perform a network level attack on Monero.