That doesn't sound like a recipe for a fast connection 
Over about 8 years VDSL went from 60/10, but dropped to 40/3, so I jumped ship to Virgin, which has the variable latency you see on BQM graphs, but I'm getting a solid 20 Mbps upload. Thankfully I made the change before this pandemic, as I've been in non stop web calls since - and the old 3 to 4 Mbps upload would have meant "no video".
The technician from the contracted IT support company who visited a couple of weeks ago reported a downstream speed of 22Mbps and upstream of 20Mbps. I'm putting money on that being a wi-fi result and bad wi-fi being the root cause of all the reported issues 
That does sound like it! Living in a flat, I've given up with 2.4GHz, especially with everyone at home, but I hit my first problem with 5GHz, someone else's router on my channel. Easily solved, but means some (really cheap) TV streaming kit (e.g. NowTV stick) can no longer see my 5GHz network.
20 years of broadband connectivity since 1999 trial - Live BQM