I would agree on powerline networks but I am suspect of the site posted. There recommend a brand that is very unkown as most their top picks with little insight to why. This smells of a fake paid review.
This site is much more unbiased but like most sites they all take adverting from these companies.
I really wish the killer company would go out of business. Most their product offering are based on hype and marketing rather than actual technology. They pretend they can make gaming faster when almost all network issues with gaming are outside the machine so they can do nothing.
Killer used to be based on realtek chipset, not sure if they still do. They just run their own drivers which is the cause of all the issues.
Most devices you find will have broadcom or mediatek chipsets in them. Intel and realtek are also fairly common.
Pretty much any card that is the same physical size and uses the same physical connections will work as a replacement.