Hi

I was wondering about Wi-Fi 6 routers and how they currently function, would appreciate some advice:

Background: Initially, I had two Netgear AC routers (R7800), one acting as main router and other as access point. Sometime ago, I bought Asus RT-AX88U, however, it had some issues handshaking with my Note 10 Plus (whenever I used to go out of home and come back on, Wifi 6 logo was displayed on phone, but the speeds would be about 40mbps. Upon turning the Wifi on cellphone off and on again, I was back to 200mbps ISP provided speed. Contacted Asus, they mentioned they have issues, which would be addressed in future firmware. I lost patience and returned the router). I then found a deal on Costco ($100 off) on TP-Link Archer AX11000 so bought it. I have blazing fast internet, improved range (removed another router behaving as access point, no need), 27 devices connected (14 of them are IoTs - 2 wireless cameras transmitting 24x7, rest mainly smart plugs), no devices dropping connection, low ping, 230 Mbps dl speed on 200 mbps Spectrum connection, overall very smooth experience. However, I had questions on how things work:

1. The Archer AX11000 - 5 G network is setup to display same SSID on both bands, but differrent channels. The router lets me only choose lower channels on one band (36 to 48) and higher on the other on manual configuration. However, I went ahead with auto settings, so my router automatically chose lower channel on first band and higher channel on other band, while carefully analyzing neighbors channels and avoiding conflicts. However, it was interesting to observe that the router always chose 80 Mhz instead of 160 Mhz. Why is this so? Is this to reduce interference? 

2. Also I observed my older devices can only accept 80 Mhz, so if I manually keep channel width at 160 Mhz, would it lead to more incidences of the devices getting knocked off (allergic!) to the router?

3. The router states 4x4 OFDMA/ Mu-Mimo. On 4.4 ofdma, each 5G band should have max throuput theoratically at 4804 mbps. Since the router is on 80 Mhz, would this mean the max throughput would be 2402 mbps... is my understanding correct?

4. Will 80 Mhz channel width on 5G impact routine functioning? I am on 200 Mbps speeds and my devices seldom ask for more than a couple of mbps as we do work at home and browse internet mainly...

5. There is one bedroom where I used to get relatively weak signals, where the R7800 Access point was kept. Even though there is no need of AP due to great range of AX11000, I am still considering placing a basic AX router there. I did some research. I was planning to get AX3000 router (2x2 transmission on 5g at 160 Mhz). However, since we generally use 80 Mhz, I decided to save money and go with AX1800 (Tp-Link AX20) router and make it my access point. It is being mailed to me, so have not been able to set it up. I thought most devices are 2x2 inlcuding iPhones, iPads  (except my Note 10 plus which is 4x4), it makes no sense buying 4x4 router for AP purposes, so wanted to save money. At some e-platforms, we can get Ax1800 at around $100 mark. Is my calculation/ decision of using 2x2 at 80 Mhz as a "just in case you need it" AP okay? Just wanted to have some tips from tech gurus!!!

6. I read articles on Forums that most Wi-Fi 6 routers are DL- ofdma only. So I assume the upload done by my Note 10 Pro in non-ofdma mode. Since we just browse or download updates and need DL bandwidth more than upload, will not having UL-ofdma make any difference? Will the devices can effectively transfer data with UL as non-ofdma and DL in ofdma? Dont the devices get "confused" (sorry for non technical words, am not a tech guy)?

Technology is interesting, would appreciate views/ opinions or answers to my points above! Thanks in advance!