iPod Touch 5th gen in 2023

1. I can't answer that one, it's your decision
2. as an iPod, and with iTunes (see point 3 below), yes. Although you need to satisfy yourself that it is in working order before you buy it and make sure that the iPod is not locked with a PIN. If it is locked, you will not be able to use it unless the seller provides you with the PIN in order that you can access it and change the PIN. As far as I know, Activation Lock (an Apple security feature) is not available on a 5th generation iPod Touch, so that need not concern you
3. Yes. If your Mac uses OS Catalina (10:15) or later, then you use Finder to manage the iPod, not iTunes. On earlier OS versions (OS Mojave, 10:14), you still use iTunes
4. the 5th generation iPod Touch can only update to iOS 9.3.5, which is an old version of the operating system. As such, there are unlikely to be any apps (apart from the built-in ones) that will be useable on it

You also need to consider how much life is left in the battery. They do wear out eventually and Apple no longer offer a battery replacement service

The 5th generation iPod Touch IS subject to Activation Lock. Please read the following info and make sure that Activation Lock is turned off, as you will not be able use it without knowing the original ID and Password. See Activation Lock for iPhone, iPad, and iPod touch - Apple Support

chamathm1 wrote:

All I want to do is listen to music and take photos. I can do that right?

Yes.