I became fed up of seeing ads and decided to do something about my lack of configurable DNS on the 5x situation*. I purchased a XikeStor SKS8310-8X - which is a dirt cheap 10Gb 8-port managed switch. I already had some 10/5/2.5/1GbE SFPs lying around. That switch is now connected to the 10Gb port on the 5x, then that switch is connected to my original ethernet setup (10Gb capable but currently a mix of 2.5Gb and 1Gb). I have tested connecting at 2.5Gb from my PC and managed to top out Virgin's 1.1Gbps throughput which was good confirmation. The switch is capable but has no descriptors at all - it is on you to figure out config elements, dependencies, etc.. Not too bad once you're in the swing of it.
There was a moment when I started looking at 2.5Gb switches instead but, for the price difference, futureproofing with 10Gb ports for not much extra made sense to me. It also means that I don't need to upgrade a switch again if I want to go over 2.5Gb - I just need to upgrade my interfaces.
My attempt to create two separate network segments failed abysmally when I realised that I couldn't configure any static routes on the 5x. Did I mention how incredibly basic this router is? I had no choice but to remain with a single subnet and segment. This will change in the future. Alas, I have setup DHCP on the XikeStor switch and finally have my DNS requests hitting Pi-hole - hallelujah. No more ads. DHCP: one less thing the 5x is doing.
Having added this into my equipment list it means that, in the future, I can acquire a WAS-110 and eliminate the 5x entirely. I look forward to that moment.
The switch was £118 and sadly didn't come with any rack mount ears despite having fixing points for them. It does have a fan which will also actively cool any inserted SFPs - this will be beneifical for the WAS-110 that runs notoriously hot. I'll do another update once I have the WAS-110 in my possession and have connected some more devices at 2.5Gb. My existing NICs top out at 2.5Gb and there aren't many 10Gb options on the market that aren't overkill for my needs; I'll wait for progress to be made in that area. There are those 10GbE Realtek NICs popping up from China but there were too many reports of general power saving features not working correctly - which defeats the point of having the power efficient NIC in the first place. I'm sure some of the more known networking brands will start producing NICs based on the Realtek chipset in the future.
*Yes, I could've configured DNS settings manually on each device, but then I have no excuse to invest in new equipment!!