Chinese low quality UTP cables are dirty cheap. There are so many those cheap cables at Amazon. But quality CAT.5e SFTP, CAT.6a and CAT.7 are not cheap compared with cheap cables. Normal home users don't need expensive quality cables though.Here's what I learned when designing network for my new house.
CAT6/CAT6A cable is super cheap, run it everywhere and often =P
if the runs are under 75ft, they will be ready to run 10GB (the longest run in my house is 51ft) in the future
all WAPs should be POE and wired backhaul (all WAPs should have 2.5gbit hardwire LAN connection sockets minimum)
always run two cables for each location
hardwire absolutely everything that is practical to hardwire (TV's, Apple TV's, Fire cubes, Fire TVs, desktops, etc etc) (if you're putting in recessed electrical in the wall for mounted TVs, run 2 Ethernet cables nearby, you'll need them) e.g. in the room I use as my office there are 6 runs. (2 locations 3 runs each). Let the wired portion of your network do as much of the work as possible, with the WiFi providing connectivity for portable devices (phones, tablets, laptops) additionally, I personally prefer Apple TV 4k's because the interface is just so much faster than the TV itself, and Fire and Roku TVs constantly bitch and moan if they aren't connected, so I hardwired them...
in rooms where things might move around, run Ethernet to 2 locations (again always 2 per run, so in a room with 2 locations that's 4 cables)
2.5gbit with POE switches are going to be expensive even if they are unmanaged. if you want to run VLANS you must use managed switches.
it's worth the time and investment to mount a network rack with a dedicated patch panel, and label everything, spend the money upfront for a 24-port or 48-port patch panel, it's a bitch to replace it later
i personally believe that its good to choose a single platform and have all your hardware on that platform, e.g. cisco, zyxel (nebula), tp-link (omada). I personally went with Zyxel.
don't use ISP supplied hardware if possible, this may not be possible with AT&T Fiber for example, but at least you can configure theirs to just passthrough to your own router.
I chose to go with pfsense for routing, and built my own machine for that purpose, i value the ability to have total control over the gateway
with the speed of networks today, even if you're only on 1gbit, i see no need to physically segment out a "mancave" network. How much bandwidth could you expect to suck up on that? Keep in mind a 4k HDR stream is roughly 25Mbit as a reference
Quality CAT.6a: over $500 per 1000ft(300m)
Quality CAT.6: over $120 per1000ft(300m)
Quality CAT.5e SFTP: over $300 per 1000ft(300m)