When a connection feels slow, the reflex is to blame the provider. Sometimes that is right. More often the bottleneck is inside the house, and the honest answer is that nobody told you how to look.
Step one: test over a cable. Connect a laptop to the router with an Ethernet cable and run the test again. If the wired result matches your package while WiFi does not, the line is fine and you are fighting your own wireless environment.
Step two: check that you are on 5 GHz. Most routers broadcast 2.4 GHz and 5 GHz under either the same name or two names. 2.4 GHz travels further but is crowded and capped in practice well below what your plan can deliver.
Step three: move the router. Concrete walls, metal mesh, mirrors, aquariums and microwave ovens all kill WiFi. A router on the floor behind a television is the single most common cause of "my line is slow" calls.
Step four: count your devices. A 20 Mbps line shared by four streams, three phones backing up and a smart TV is not slow — it is busy. The portal shows per-device usage if you need evidence.
Step five: restart the ONU and router, in that order, with a full minute unplugged. Step six: update your router firmware. Step seven: if all of that is clean, open a ticket with the wired speed test attached and we will look at the segment.