[stomachmonkey]

The advice to just hang your own router is correct.

The alternate option, since you are only buying Internet from your provider, you may be able to buy your own modem and not have to rent theirs.

If I had to guess, based on your symptoms, your previous router was 2.4ghz only and the new one is dual band, 2.4 and 5. Or if it was dual band your devices were attaching to the 2.4 band.

One frequency is not really better than the other, they both have their pros and cons.

2.4 provides a strong signal over longer distances and handles vertical obstructions better than 5 but it's slower and the channel spread is smaller making it more susceptible to interference.

If the new router is dual band and if both radios are broadcasting SSID see a) which band your devices are connecting to and b) try the other.

The 5ghz frequency also has one other oddity that shows up sometimes, when devices attach to the higher channels in the spread they behave inconsistently. If they are attaching to the 5 band see if using the lower tier of channels helps.

One of the other issues with 5 is there are restricted channels. Weather radar operates on the 5 band and if there is radar in the area (do you live near an airport) the router is designed to drop the channel if it detects radar because it is not allowed to cause interference.

So, option 1, turning off IP's routers wifi and hanging your own will most likely fix the issue but not guaranteed to.

If you feel like dicking around with it, from a PC connected to the router via Ethernet use your web browser to log into the router back end, it's usually 192.168.0.0, 192.168.0.1, 192.168.1.0 or 192.168.1.1

User and pass should be on a sticker on the back of the router or try the common defaults, admin / admin or admin / (no password). You can always google the router make and model for the default if no sticker is present.

Check your 5 band settings, force it to use channels below 150.