Mbps doesn’t increase after changing frequency band to 5ghz.

I have 1gbps internet from my provider but i only get around 30 sometimes less than 20mbps, i even had a time where it showed kbps. I thought i found the cure but changing the frequency from automatic to strictly 5ghz it did not change for me. It did change for 95% of other ppl. Anyone else that had the same but maybe has the way to still get the fast wifi?

My ps5 is also on my room and the router is downstairs. I use (tp link) wifi boosters/wifipoints with ethernet ports and so i have cable internet on my ps5 in my room. Would something about this be the problem?

Thanks in advance