Probably. In fact almost certainly. Next time you have very slow just try it instead of rebooting. Leave it disconnected for a couple of minutes or so.
The other thing that may be worth trying at some stage is a Factory Reset
of the router. Unless you have any settings of your own then that can sometimes clear problems. Do you know how to do those?
If you don't, you do it while it is connected, though you could disconnect the PPP. There should be a tiny hole somewhere marked Reset
, with a microswitch inside. You press that gently but firmly for 7-10 seconds with an opened-up paperclip, until the lights go out or start flashing. It then reboots after a while and sometimes works wonders.
It needs doing before anyone can be sure it is faulty, rather than just congestion on the network.
Kindness isn't going to cure the world of all its awfulness but it's a good place to begin. Daisy Ridley.
My broadband basic info/help site - www.robertos.me.uk.
Domains, site and mail hosting - Tsohost
Connection - AAISP Home::1 80/20. Sync 65618/13914Kbps @ 600m. BQMs - IPv4