The third season leaves Korra crippled and I always need answers . So I googled whether she could ever walk again and it turns out that she can after 2.5 years under Katara's care but she can't go into the avatar state anymore. Is this true?
As explained here Can the Avatar still be reincarnated?
Actual Avatar reincarnation means Raava accepts part of current Avatar soul, leaves its body, and finds new Avatar. Communication with previous Avatar incarnations was exactly communication with parts of their souls inside Raava. Since Raava got itself destroyed, and then resurrected, it is in "clear" state, without souls of previous incarnations.
But while Raava exists in this world, it can find new vessel to become next Avatar incarnation. The only consequence of its temporary destruction is that Korra is now much like Wan.
so the Cycle is thought to have been reset, so even if Korra could it wouldn't mean much since the Avatar State, as explained to Aang by Roku, is when the Avatar taps into the power and knowledge of previous Avatars.
That being said she is shown in Book 4 entering the Avatar State when
she protected Kuvira from the Spirit Energy Canon, holding it back and causing the explosion which created the third spirit portal
and she is also shown going into the Avatar State in a non dire situation in the Turf Wars Comic when intimidating Wonyong Keum, the CEO of Keum Enterprises