Yeah I've just been reading up on that, I had no idea. It seems you need a device that supports balance-rr so it isn't as simple as using anything supporting standard LAGs. It seems that Mikrotik devices do support balance-rr and of course a Linux box would too.
On a separate note, I received a Hub 4 despite only ordering 500Mb. I had read of this happening in areas with high utilisation but I didn't know what the actual technical reason was, but after doing some digging it seems that the Hub 3 only supports 24 downstream channels whereas the Hub 4 supports 32. I haven't seen a Hub 3 to check but my 4 has indeed locked on to 32 downstream channels so I guess that's the reason. It seems to be working ok so far, although the logs do show an occasional message:
RNG-RSP CCAP Commanded Power Exceeds Value Corresponding to the Top of the DRW
Doesn't sound great, but I've had no speed problems and it's only cropping up in the logs once every 3 days or so.