Your router is in a cabinet. That's the problem.
Wood, glass, and especially metal eat Wi-Fi signal for breakfast. Your router is broadcasting through a thicket of obstacles before the signal ever reaches the room you're in. 5 GHz and 6 GHz (the fast bands) suffer worst — they have shorter range and weaker penetration than 2.4 GHz. Faster internet won't fix Wi-Fi that can't escape the cabinet.
Sit it on top of the cabinet, or on a nearby shelf. Re-test in 10 minutes. This is the highest-impact free fix on this entire site.
If the cabinet is the only place the cable line reaches, run a $15 ethernet cable to a more central spot and put the router there. Ethernet will outperform a $500 fiber upgrade every time in this scenario.
Faster internet into the house can't fix Wi-Fi that can't escape the cabinet.