Look at PoE as from the PoE power source to the PoE device. In you case this is from the PoE switch to PoE cameras. Each camera needs its own cable run back to the switch, they cannot be shared from one run. (yes have seen this IRL)
For each of the cable runs from the PoE switch to the PoE devices, make sure the cable is NOT CCA (copper clad aluminium) because CCA is not good for PoE. CCA cable is almost always cheaper, and if used with PoE you will have problems.
In general the PoE limit is the limit of the cable spec for Ethernet CAT5e/6 which is 328 ft. If you need to run over 328 ft, (100M) add a switch somewhere in the middle and place the PoE switch at the end near the devices that need PoE.
There is a new Ethernet cable product that allows runs greater than 328 ft. (100M) with PoE support called Game Changer cable. Tom did a video on it here at https://www.youtube.com/watch?v=ZY48KUAZKhM
A cable that pulls and terminates like a CAT6 but can deliver 1Gbps and PoE+ over 200 meters - that’s a GameChanger!