My parents have 1 router and 1 extension router which bost about 6 connections coming from them (all of them show varying degrees of the same issue for my PC) some connections are 5 GHz some are 2.4 GHz. I may not have understood your question, were you asking for the specs of the main router?
My WIFI device is an internal PC "Realtek RTL8811AU Wireless Lan 802.11ac USB 2.0 Network Adaptor"
getting a new wifi card is your best bet.
a 2x2 card would be much better, and ac is the old (still most relevant, but its starting to get replaced) by ax wifi
or wifi 6 with the new naming scheme.
so a 802.11ax 2x2 card would be your best bet, and connecting through 5ghz, as long as the signal is good enough, will be faster.