Ethernet cable options

So, having decided not to move home but to stay put and upgrade it, I'm going to be paying a professional to cable between the three floors of the property.

The logical stuff is what I do, so 2 cables from top and ground floors meeting in the home office on the first floor, 802.3ad bonding. Initially cables to run at a gigabit each, moving up 10 GbE later.

Anyone see any benefit in spending extra on 2 GHz pre-standard Cat 8? I'm thinking that over those distances high quality Cat 7 will be fine even to 40 GbE and being able to run a 20Gb LAG should be good for a long time yet.

Regarding the rest of the logical stuff the network will be a high powered wired router from Ubiquiti for WAN connectivity, a smart switch on each floor as backbone, additional switches as needed for port density, and an 802.11ac access point on each floor for wireless, though 2.4 GHz radio active on top and ground floor only due to lack of channel availability.

As Cat7 will run at 10Gb over a 90 metres you will certainly not have a problem installing it. I cannot see any benefit of going to Cat 8 especially for cost being probably twice that of Cat7 which itself is over twice that Cat6A.

Given that 6A should support 10Gbps is there a need to use Cat7 ?

Fibre?....it would then be totally future proof.

Just require investment in switches with a SFP port or two.

From that venerable source wikipedia:

Category 8 is designed only for data centers where distances between switches and servers is short. It is not intended for general office cabling.

Max 30m to 36m depending on patch cable length.

What the OP intends would be running short lengths - at a guess probably 10m or less but still, to me, not worth doing.

Cat7 and Cat8 aren't just down to what cable you use - a compliant install will require the right connectors, termination methods, patch panels, the runs have to be done in a certain way (bend radius, proximity to other cables/pipes/etc, fastening), and some other things.

Fibre (multimode should be plenty for your kind of short distance) would indeed be the best choice, and frankly not that expensive nowadays. If you want copper, then Cat7 (or even 6) would be enough.