They do make 36s, but they are only common in industrial, farming, and mudding. If this was a dedicated off-road vehicle or mudder, you could definitely buy 36s and mount them (most I've seen are ~14 inches wide). But you won't find anything road-worthy at that size.
And yes, as you said... 35s are usually around ~34.5-inches, 37s are around ~36.5-inches, and 36s are usually around ~35.5-inches—give or take a few tenths of an inch. In the past, tire sizes were measured by the diameter of the mold rather than the actual finished & mounted tire. The Europeans have since moved on to a more accurate euro-metric sizing system. But for whatever reason we in America like to mis-label things. It's like 2x4s—why is a 1.5-inch by 3.5-inch piece of wood called a "2x4"?? I dunno, cause 'murica!... I guess. 🇺🇸
2022 4dr Badlands, 2.3L Manual, Mid pkg
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Moving Chicane, Deano Bronc