PoE is 48 V though many believe it's only 24 V, the usual automation PELV/SELV voltage. One should check the current requirements and voltage drop. I never had any issue but had to check how many ampères (current) could be supplied as that depends on the used devices.
Also not all ports of a PoE supplying device are necessarily PoE-capable. More I can't really remember, I don't touch anything related to computers and networks as long as everything works fine and hasn't to be modified for a *V*E*R*Y* good reason. I absolutely hate Microsoft software but must run Windows as Linux isn't a viable option.
Also I never outsource anything related to computer or networking, so I always know what I have and how it is set up (at least until MS messes it up remotely during some stupid update, indeed that risk is higher than any virus, someone at MS could worldwide crash most computers with Internet access, causing thousands of billions USD (or CHF, EUR) damages).
Cameras may require additional power for IR light, heating, pan and tilt, etc. Just do the math if power requirements are listed in detail.
One should try to get the PDF user manuals first to check how detailed the installation instructions are. If there are networking problems it's very easy to open a Pandora's box when starting to play with settings. Many wannabee network specialists (me included) start editing settings more or less randomly crossing fingers (but I document the initial settings).
Also true network experts are not that easy to find and won't usually staff call centers.
Also here, using widespread products makes it easier to get help from online communities, sounds obvious, I know.