GS308E VLAN to separate home devices

Wow, schumaku .  Thanks for the very deep coverage.  I think I'm following, but I'm also NOT very well versed in networking.  I'm a pretty intelligent and capable guy, but honestly don't entirely understand the difference between subnetting and VLANs (other than the basic idea that the former is more "concrete" of a separation).

What about something like this person's configuration: https://community.netgear.com/t5/Smart-Plus-and-Smart-Pro-Managed/How-do-I-configure-VLAN-with-Netgear-GS308E-and-Edge-RouterX/td-p/1948574

Getting an EdgeRouter for the "top-level" connection to the ISP, and using my Nighthawk as an access point for one "leg" of the network?  Specifically, I'm looking at their [Local Network.jpg], and using the Nighthawk as AP1, and my Linksys as AP2.  From what I've read, the EdgeRouter will do all of the "heavy lifting" of routing and as a DHCP server for each VLAN.  And from what you've written, I'm thinking that the GS308E would be necessary instead of a dumb switch, to properly navigate "up" to the printer (and NAS) connected to the EdgeRouter on eth2?

In addition to the Nighthawk X4S and Linksys EA4500, I also have a Netgear ProSafe GS108E, and two TP-Link SG105's.  The GS108E is just being used as a dumb switch, because I recently got it from a friend, and upgraded one of my TP-Links to it for 8 ports vs 5 ports.  I see from this page that it might be capable of more, but it's not capable of L3 routing or anything...  Unfortunately, I'm an accountant and web dev (frontend only) by trade, and while I'm very eager to learn more, I don't know what I don't know.