@woozle thank you very much! Understood. 

Would you recommend another/better way to achieve the same effect?

  @arsradu 

Unfortunately, there is no effortless way to achieve the same.

Of course, the perfect solution would be to buy the product lines that support the desired feature by design.

Anyway, to solve the issue for your IoT devices you could just connect them to the Main EasyMesh network, which is extended by the Satellite router.
For the Device Isolation feature (menu "IoT Security") it doesn't matter whether a device is connected to the Main network or the IoT network (at least on the C80, C64, A8, C6 V4 router models). Thus, there is actually no need to use the "IoT" network.

And if your guests are not too demanding about the Internet speed, then set up a wholly separate network infrastructure for them using some cheap 2.4 GHz equipment.

As second-hand devices routers like the TL-WR840/841, TL-WR940/941 can be had for very little money on eBay and if you bridge two of them together via WDS, then you would have the same coverage as the two Archer C80.
 

  @woozle very good tips!

Actually initially I had my IoT devices connected to the Main network. :)) Just recently switched to the dedicated iOT network. 

And the IoT devices are already connected to the main router and there's no need to connect them to the satellite. It's just something I noticed when trying to set up Guest network on the satellite.

So there won't be any issues switching them back to the main network, or just leaving them like this, since they're only needed near the Main router anyway.

So I was more interested to set up the Guest network. And with a Mesh setup I see that's not possible.

For future hardware upgrades, I'll definitely be considering a Deco setup. But it feels like a step down to be able to configure it only through the Deco app. Never used it, so I don't know if you can get into the same level of advanced settings as you can with the C80 for example (on the web interface, not the app). But if you can, that's definitely an option I'll keep in mind.

But so far, the idea would be to get this solved with the resources I have at hand, or at least with minimum investment. So yeah, I'll definitely look into purchasing a pair of second hand routers for my guests. 

I was also considering turning off the Mesh feature and using WDS instead to extend my network... Any idea if that would also solve the guest network issue?

I would do bridging but I don't currently have a cable that long.

Anyway, very good tips. Thank you very much! I'll definitely think about it! :)

arsradu wrote

 

I was also considering turning off the Mesh feature and using WDS instead to extend my network... Any idea if that would also solve the guest network issue?

 

  @arsradu 

Since you can freely and individually configure both C80 routers when they are connected via WDS, I see no reason why you shouldn't able to create a guest network on the secondary C80 as well.

But keep in mind that when connected via WDS you wouldn't be able to isolate the guests who are connected to the secondary C80 from your home network.

So, this solution would merely allow you to have a Wi-Fi network with a separate password for your guests.

  @woozle yeah. That might do it. :)

Thank you very much for all your feedback!