Wore out three sets of tires already!
It is true 700mm is 27" +/- but I think it's all to confuse us and is doing a pretty good job.So the 700 is not centimeters or millimeters, although 700mm would equate to about ~27.5 something inches.
The 622mm dimension might be used for 700c wheels, which might fit either 28” or 29” tires.
Older 27” rims like on 10-speeds are 630mm.
Some tubes are sold by the range of tires that they might fit (like as marked on the box), but some sellers only state one of those sizes.
Recently, the last 27” x 1+1/4” tubes that I purchased were marked on the box to also fit other sizes (e.g., 700-something). I believe that the markings, molded into the tubes, indicated a metric size.
I try to stick with ISO size then knowing 27.5 and 29r are to be avoided in my life.
I hope I don't get an itch for an old 28" tire bike.