So, I've been researching a bit about 51% attack potential against the Bitcoin network.

As per my understanding, with a successful 51% attack, an attacker can confirm invalid transactions and do double spending of BTC. They can probably reverse recent transactions too.

Are there any capabilities built into the code of Bitcoin or Bitcoin mining node softwares to tackle a scenario like this?

Since majority of the hashing power is controlled by the adversary in the case of 51% attack, they can literally do anything for as long as they can sustain the attack.