Likely
Your Wi-Fi can't reach that room. Get a mesh.
Single-router setups have dead zones. A back bedroom or garage office two walls away from the router can drop from 700 Mbps to 8 Mbps without anyone noticing — until you try to take a call there.
Try this first · Free
Move the router to a more central location
Ideally elevated, out in the open. If your ISP installed it in a far corner near the cable entry, you've found the problem.
If that doesn't fix it
Add a mesh system
A two-pack Eero, TP-Link Deco, or Asus ZenWifi runs $150–$250 and ends the dead-zone problem. Wi-Fi 6 is fine for almost everyone — don't overpay for 6E or 7 unless you have devices that use 6 GHz.
Fiber? No
A faster connection to the house doesn't reach the bedroom either. Mesh first.