Whats wrong with my Internet?

I have Xfinity 300mgps plan and device is "xFi Gateway", whenever I do a "Speed Test" It looks like my internet is performing as promised.. however when I try to online game, I will frequently just lose connection to discord and the server for a minute straight. I am on ethernet and it doesnt change anything. My wifi signal always shows like one or two bars. Its not even just slightly higher ping, it just completely makes me a robot on discord and disconnects me from games. Browsing the web is even slow to load the new pages.

Im in florida and the first few months it was perfect, but for like half a year now its just so bad. Any fast paced online game is unplayable.