Perceived Hub 4 Wi-Fi strength degradation

Hi - been using Hub 4 for about a year now, and until recently its Wi-Fi strength in all but the furthest locations of my house has been robust and stable. I'm running a combination of 2.4 and 5Ghz devices, with the 'cleverer' ones achieving dual-band. The hub's Wi-Fi signal is in default configuration, with Enable Channel Optimization enabled and channel selection is automatic for both frequencies.

No complaints until maybe a month or so ago, when my Win 11 laptop that usually sits upstairs in my office started to become unable to stably handle the usual Teams calls, screenshares, etc. Meanwhile other 2.4Ghz devices in the same room as the Hub 4 will briefly go offline from time to time. 

The Hub has always remained in the same place - albeit behind the TV - and yes berate me for this - but it's been absolutely fine there for my needs. 

The Hub 4's Wi-Fi troubleshooting capability is pretty much nil and as a last measure have just resort to reserving all of the c.25 devices' IP addresses and increasing the lease time to 7 days to help cut down on DHCP chatter. Its temperature is always hot to touch but the diagnostic tool doesn't complain.

I'm looking for options now - I don't think Pods will solve this problem, I've used a similar TP-Link solution and wasn't particularly impressed. Should I look to invest in my own wireless router and switch to Modem mode or should I seek to have an upgrade to Hub 5 with its stronger Wi-Fi 6 capability? 

Any advice welcome.