Saha is a trichiliocosm, Sukhavati is a trichiliocosm, Vaiḍūryanirbhāsa is another trichiliocosm and this is infinite.
Well, it is said that a trichiliocosm is limited in space (but is huge!). Some masters equates a trichiliocosm with a galaxy.
This is an horizontal cosmology.
Each trichiliocosm may contain 28 realms of existence (our Saha does). Perhaps other trichiliocosm, depending on the karma of the living beings there, may have more or less than 28 realms, perhaps other realms does not have hells, or maybe they don't have human realms, etc. This is a vertical cosmology.
Now, thinking of Amitabha, its description does not fit with a trichiliocosm. A trichiliocosm includes stars, planets, suns, moons, four continents. If we read PL sutras, there is no Mount Sumeru and is describes as one land, not as multiple lands of Mount Sumeru, four continents, with stars, moon and sun. The only thing that I found to match with a trichiliocosm is that it is the realm of Buddha Amitabha.
Then Ananda asked the Buddha, "If, World-honored One, there is no
Mount Sumeru in that land, what sustains the Heaven of the Four Kings and
the Heaven of the Thirty-three Gods?"
Also, since each trichiliocosm has a vertical cosmology, Samsara are the 6 realms (28 planes), there are also 4 Enlightened realms, I thought that Pure Land was some kind of "physical, material, observable by humans, subject to law of physics, the same physical plane as us", but thinking on this, Sukhavati can be in any of the 10 realms, why it has to be on the "Physical world" where there are other 9 realms? Also, it seems more plausible if the Pure Land is in the 10th realm, the realm of the Buddha, the Buddha Amitabha. So, in this way, Pure Land is not subject to birth and death nor to Samsara, because it is one of the 4th realms not subject to Samsara, the Buddha-realm.
Is there something wrong in my reasoning?