I use a PCI (the internal Intel PRO/Wireless 3945ABG) and USB (linux reports it as Realtek RTL8188EUS, but really a TP-LINK wifi...) wifi devices on my laptop running Ubuntu 20.04.4LTS, plus there's the wired LAN for internet access. I have Conky working fine for monitoring network using this code for the NETWORK section:
${color orange}${font Ubuntu:bold:size=10}NETWORK ${hr 2}
${font sans-serif:normal:size=8}Local IPs:${alignr}External IP:
${execi 1000 ip a | grep inet | grep -vw lo | grep -v inet6 | cut -d \/ -f1 | sed 's/[^0-9\.]*//g'} ${alignr}${execi 1000 wget -q -O- http://ipecho.net/plain; echo}
${color lightgray}${font sans-serif:normal:size=8}Down: ${downspeed enp0s25} ${alignr}Up: ${upspeed enp0s25}
${color green}${downspeedgraph enp0s25 20,150 } ${alignr}${upspeedgraph enp0s25 20,150 }$color
${color lightgray}${font sans-serif:normal:size=8}Down: ${downspeed wlx8416f91d3f6d} ${alignr}Up: ${upspeed wlx8416f91d3f6d}
${color green}${downspeedgraph wlx8416f91d3f6d 15,150 } ${alignr}${upspeedgraph wlx8416f91d3f6d 15,150 }$color
${color lightgray}${font sans-serif:normal:size=8}Down: ${downspeed wlp2s0} ${alignr}Up: ${upspeed wlp2s0}
${color green}${downspeedgraph wlp2s0 15,150 } ${alignr}${upspeedgraph wlp2s0 15,150 }$color
${color blue}${font sans-serif:normal:size=8} ${voffset 5} Wireless» $hr${color green}
${color yellow}${wireless_essid wlx8416f91d3f6d} ${color red}${alignr}Signal: ${color orange}${wireless_link_qual_perc wlx8416f91d3f6d}% ${wireless_link_bar 4,100 wlx8416f91d3f6d}
${color yellow}${wireless_essid wlp2s0} ${color red}${alignr}Signal: ${color orange}${wireless_link_qual_perc wlp2s0}% ${wireless_link_bar 4,100 wlp2s0}
The IP's show fine for all three (PCI/USB/LAN), the down/up and graphs do fine for all three, but I get to the wifi signal strength graphics and the wlp2s0 (PCI) works, but the wlx8416f91d3f6d (USB) does not - it says signal 0%
Any ideas why this is happening?
Here' a pic of the area:

OK, new "wrinkle": I can switch the USB wifi to ATTTtkHm7i_EXT (my extender) and both signal strengths work. I can even set both wifi's to ATTTtkHm7i_EXT and both signal strengths work, just when both are on ATTTtkHm7i, the wlx8416f91d3f6d goes dead... also, I can rem out the PCI wifi (wlp2s0) so only one signal strength displayed, and wlx8416f91d3f6d (USB wifi) is still dead... my USB wifi (wlx8416f91d3f6d) just doesn't seem to be friendly to ATTTtkHm7i ~ well, just doesn't like to report signal strength, but still down/up loads fine.
I know you guys hate people that bring up stuff like this, but I also have DeskTopInfo (AKA "Conky for Windows) for my Win7 on the same laptop, and I know I'm comparing apples and oranges with differing OS's and differing programs, but the two wifi signal strengths work fine in it and both using the same ATTTtkHm7i ~ just sayin'