when you have to sign in with an ID password, it means that your company is using WPA2 or WPA3 Enterprise. There is an authentication server that processes your credentials and grants access to network resources based on the network access control policy.
It is not possible to answer your question without knowing the details of the network access control policy.
what model is your access point? is it the Asus? is it in Access point mode?
you should be fine on that router.
you dont need 6E, most likely. Get the EAP670.
(that being said, you probably dont need 2.5Gbe either)
almost certainly your router and adguard installation only respond to web management on their own subnet.
Get a router that can actually do a PPOE Passthrough without NAT, such as a mikrotik.
may be a bit difficult to configure though.
DMZ on home routers is basically a 1:1 NAT with no firewall. so DMZ working correctly will still NAT.
if the issues are isolated to physical areas, the internet package isnt the problem.
so in that cases, mesh routers may be an option that works.
dont set any PVID, or leave it on 1.
no i didnt indent to highlight that portion. just the first sentence.
Does this make sense?
not really.
Are there any consequences I am not anticipating? Are there any performance considerations?
your IP scanners are gonna run a lot slower..other than that no. large networks are usually a symptom of a larger issue, but not a problem in and of itself. If for example you have 50 devices, putting them on a /24 or /20 or /21 wont likely make a difference. but if you have 1000 devices, deciding to solve that problem by creating a /20 does NOT solve the problem of 1000 devices on the same broadcast domain. but dont conflate those problems with "dont use large network sizes such as /20 or /21". does that make sense?
I'll never have 254 devices on this network, let alone 254 on a single subnet. Should I be... "spreading out" the assigned host addresses? Like instead of .1, .2, .3, assign them .8, .16, .32, etc.?
Most people do what you are doing but dont increase the network size just to do so.
for example, instead of 10.0.0.x make it 10.0.0.200-254
instead of user A's devices being 10.0.1.x make it 10.0.0.10-19, 20-29 for the next user, 30-39 etc.
then the DHCP range make 100-199.
that way you still have equal "tidiness" without needing a humongous network size. but its up to you.
half the things you say you need are much better handled on business class equipment.
the only hang up you have there is that wifi on business class is kind of expensive.
i'd suggest something like a mikrotik router and two aruba instant on APs.
look up surface mount keystone box. thats the best you are gonna be able to do.