Gojo and Yuji had been the first to enter the Solitary Buhhda realm. Much like in the greek realm, Gojo decided someone can only call himself a proper sorcerer after stepping into the 2nd realm, the sophic realm equivalent. So the progression goes: curse user, sorcerer, Pratyekabuddhayāna (solitary Buddha), Bodhisattva (savior Buddha), and emptiness (Olympic equivalent).
So my guess is that it works something like this, right?
Śrāvakabuddhayāna (Assisted Buddha): Not really a Jujutsu Cultivation Realm but rather a failed attempt at entering the Pratyekabuddhayāna Realm. They either failed to become a Solitary Buddha, have no interest in becoming one, or simply have very poor talent in Jujutsu. Either way, they still wish to be Liberated from Curse Energy but require the assistance of a Samyaksambuddha who can forcefully purify their Curse Energy into True Positive Energy but at the cost of becoming an Arhat, also known as an Assisted Buddha. This means that, while they still possess powers on par with Solitary Buddhas, they will need to wait until their next life to be able to become a Bodhisattva.
Pratyekabuddhayāna (Solitary Buddha): One who has obtain Liberation but has yet to or unwilling to aid and guide others. At this stage their Curse has been completely purified, becoming True Positive Energy, not the false positive energy of Reverse Curse Technique. True Positive Energy is able to purify surrounding Curse Energy solely from contact. This causes Curse Spirits to weaken if not outright exorcised just by being in their presence. This means it can be use to negate Curse Techniques and nullify Curse Tools and Items.
Bodhisattvayāna (Saviour Buddha): One who obtained Liberation and is now working to aid and guide others. They need not literally preach or give sermon like Geto, and can instead aid and guide through example and demonstration like Gojo and Yuji. So long as their actions aid and guide others towards Liberation then they can be said to be performing their duty as Bodhisattvas. As Bodhisattvas, they collect and accumulate Faith and Gratitude from followers and once it reaches critical mass, they can push through and break into the Realm of Samyaksambuddhayāna.
Though, I think the Olympic Realm equivalent should be
Samyaksambuddhayāna (Complete Buddha): One who has obtain Liberation and has guided a great many other towards their own Liberation. In this realm they no longer require a Physical Body and can exist a being of pure consciousness alone. However, they can still interact with the rest of world if they want too by creating and projecting a body made out of True Positive Energy similar to those pre-mending Planeswalkers from the old days of Magic the Gathering. They can forcefully purify a person's Curse Energy but at the cost of them becoming an Arhat.
Edit: As for the Realms beyond Olympic.
The Titan Realm equivalent should be
Sambhogakāya Buddha (Celestial Buddha): Involves the Construction of a Celestial Egg/Reality Engine and is a blueprint for their very own Pure Realm. Extremely similar to Sukuna and Kenjaku's Barrierless Domain Expansion but on a completely different scale. It is essentially a mixture of Reality Marble and Marble Phantasm that's also an ORT level Reality Overwrite with the immutable properties of the Garden of Avalon.
The Primordial Realm equivalent should be
Dharmakāya Buddha (Primordial Buddha): Involves the hatching of the Celestial Egg, thus detonating a self contained Big Bang within themselves, gaining a Cosmic Body and embodying their Pure Realm. It is essentially similar to Gojo's Domain Envelopment but on a completely different scale. At this point they basically become a walking talking Universe and are basically a God from Shinza Bansho that also possesses both Gudou and Hadou qualities.
Something along this line.
