I just got the TP-Link AX1800 (the manual says AX1800 / AX20, the router's firmware tab says AX21, so....), and I want to use it as basically an Access Point, but I also want to be able to get to the control panel via wired PCs, and possibly add additional wired clients to the AX1800 (this means I can't use the AX1800 Access Point Operation Mode).

Currently,

• I have my AT&T fiber modem in the basement. It acts as my "main" modem, i.e. DHCP, NAT, etc.
• I have a Cat-5 cable that runs from the AT&T modem to a 16-port switch upstairs. Everything on my network is connected via that switch.
• I have a cable going from one of the AX1800's LAN ports to the switch.

I have mde the following config changes (i.e. delta from factory reset):
Internet:
- Left connection type as Dynamic IP
- Disabled NAT (AT&T modem handling)
LAN:
- Changed the IP to 192.168.0.2 (to avoid conflict with my AT&T's 192.168.0.1 IP)
- Changed the subnet to custom 255.255.252.0
DHCP:
- Turned off DHCP (AT&T modem handling).

Here's what works:
- I can connect wireless devices and get to the internet. Looking at the IP configuration of my laptop, everything looks great.
- I can get to the control panel from wired or wireless clients at 192.168.0.2
- DHCP (from AT&T modem) works fine - no conflicts

Here's what doesn't work:
- It keeps telling me I have no internet connection (but my connected devices can actually get to the internet)
- Things that depend on an internet connection like Dynamic DNS won't work
- On the Internet tab, under the Dynamic IP section, everything is basically blank. The IP, subnet, gateway, and DNS's are all 0.0.0.0.

Here's what I've tried:
- Running the cable from the AX1800 WAN port to my switch (instead of from a LAN port). I forget if this worked, but I know I coudn't access the control panel from my wired PC any longer
- Running an *ADDITIONAL* cable from the AX1800 WAN port to my switch (meaning I had a cable from a LAN port to the switch PLUS a cable from the WAN port to the switch). BAD IDEA! I didn't think this would work - and it didn't - but it also really screwed things up. Even after removing the WAN cable, when I would ping 192.168.0.2 (the AX1800's IP) the traffic would be hitting the IP of whoever issued the ping command (i.e. it was looping back). I had to factory reset and start over
- Changing to Access Point Operation Mode, and running cable from WAN to switch. Again, I forget if this worked, but I know I wasn't able to get to the control panel from my wired PC.

Here's what I want:
- Devices connected to the AX1800 via wires or wireless to be able to get to the internet (duh)
- Ability to connect to the control panel via wired or wireless
- AX1800 to recognize it has internet access so things like DDNS and TP-Link ID work

With my old Linksys modem, in addition to "Dynamic IP", it had an option for "Bridge Mode" that seemed to do what I want.

The AX1800 has a "Bridge Mode", but only under IPv6 config.
 

I feel like maybe I need to change the Internet settings to something besides Dynamic IP, but I don't know what I'd change. None of the options seem like a better fix except maybe Static IP - but what would I put in there?

(I sent an email to tech support, but they seem to be pretty busy, COVID-wise)