I saw some mention in other places that EL10 will require X86-64-v3.
Does anyone have any information about whether this will be the case?
I just checked and out of my six current computers there’s only one (laptop) that has X86-64-v3. 
I might have to start considering my options if this actually goes ahead.
Yes, this is precisely the case. x86-64-v3 is a hard requirement for el10.
EL 9 (and thus Rocky 9) will be supported until 2032. You’ve got time to plan a hardware update or two. 
In my homelab I’m slowly replacing the gear that can’t run 9. Down to just one more server and one really nifty special build that are still on 8. And I’ve got one box that won’t run 10 either. But I’m in no rush. There’s plenty of time for both. 
Yeah it’s unfortunate, but then it’s a reality. Whilst hardware technically can work a long time, software moves on and it’s hardware requirements change. It’s no different whether you use Windows, Mac or Linux.
Theoretically I could still attempt to use a computer I had from the mid 90’s - AST Premmia GX, Pentium Dual CPU - it still worked but nothing could be ran on it so it was ditched. NT 4.0 was good on it, could take advantage of dual CPU which Windows 95 at the time could not.
Hardware doesn’t last forever and is made redundant unless we use the older OS"s that we could run on it. In reality though why would I even attempt to use it since it would be so slow. This is also no different for a computer I have from 2008 - Core 2 Duo, 8GB ram. Probably about all it could be is a web server now, not even a great one.
As already mentioned Rocky 9 until 2032 - 8 years of usage without having to worry about changing. At that point your hardware will most likely be slow if not broken and replaced with something newer.
Some could blame “software bloat” for hardware becoming slower.
Old hardware consumes more energy and achieves less. The energy bill is a thing.
Making (new) hardware consumes natural resources and discarded gear is waste.
Then again, repairing old hardware is not without a cost either.
Both “keep old” and “get new” camps do have their points.
Not only that, but at current cadence RHEL 12 would release in 2031, with who-knows-what hardware requirements. Don’t buy before you know?
If you have a server (software) that can run to 2032 with Rocky 9, then let it run.
If you “need” the latest versions of this and that software (which is not really the forte of EL distros), then you will hop to new distros (and new hardware) much more often.
Can anybody confirm whether or not there is any option for emulation of -v3 on -v2 hardware (as a means of being able to run EL10) ?
Unlikely, any kind of emulation would be slow anyway so pointless.