@Kevin_Z 

Connected via 2.4G. While the signal is good, which is most of the time, I have download speeds around 30Mbps which is what I would expect. Once the ping to the router climbs, everything slows down with downloads capping at about 0.3Mbps, and pings to all websites over 150ms, but it is still somewhat servicable for browsing.

Since making this post, I've verified that it persists even when my PC is the only device connected to the router. The issue begins intermittantly around 6pm, I assume because activity from neighbours increases. I hope you have some ideas I can uses to troubleshoot, I feel as though I'm never going to get to the bottom of it, let alone fix it without investing in wifi extenders or something which I hoped I wouldn't need with the A10.

@Kevin_Z 

I grabbed some software to do a survey and I think I understand the issue. Normally, my router picks a mostly empty channel between the neighbours and reception is great. However there is a local network here called "VodaphoneConnect" which seem to be using a very powerful transmitter. This usually sits in another vacant channel, but every so often, it jumps across into the channel my router is using which degrades my signal a ton (I have better reception with their network than I do the router in my own house).

Unfortunately, the 5g doesn't give a great signal throughout the house. I take it there's nothing I can do besides find a band this other network won't drown me out on?