I don't follow hardware revisions (mostly), because they're usually just different BOM items (due to material sourcing issues) and not important in the WiFi scheme of things. The exception is what
@wouterv suggests though. v4 of the RT-AC68U has greatly improved hardware and would be worth singling out. But I wouldn't waste time doing that today.
As long as you're buying a newer RT-AC86U than the 'original' from 2017 or 2018, you should be fine. The last one I remember looking at was a 2020 model version which is still working for many customers that don't need to upgrade today. I'm not sure if there are newer models for that line.
The RT-AC86U is a far better buy than any version of the RT-AC68U and/or RT-AC3100 (and their cousin models), even today. Depending on your actual costs, (and be sure you can wait/look for sales too, of course), the AX models are superior and may be worth it if you plan on keeping your router for more than a year or two.
I don't believe any purchase of a home router today is 'overkill' because they are all underpowered, IMO, (of the models I suggest in the link above), it is simply a matter of perspective of how long you want to keep your new purchase and have it be useful far into the future.
If you haven't discovered them already, the following links give you an idea of what the newer router platforms may offer you. And why I think buying 'yesterdays' tech is always a bad idea when something better is available, even at a higher cost. Sure, hard budgets are important to stick to, at times. But usually, I find, budgets are arbitrarily arrived at, without taking into consideration all the benefits vs. the additional costs.
Is Wi-Fi 6 Worth It
Wi-Fi 6 Pt 2
RT-AX88U Upgrade https://www.snbforums.com/threads/b...ta-is-now-available.60037/page-31#post-531024
RT-AX86U vs. RT-AX88U
Report - 2x RT-AX68U upgrade over 2x RT-AC86U in wireless backhaul mode
And it is worth pointing out that while all the information above is true and accurate for the specific WiFi environments the specific hardware compared was tested in, it bears repeating that you should be doing your own tests in your own unique network environment and judging on your own if the value is there for you too.
I realize for most home users it is impossible to 'know' if the value is there or not if they're just testing one or two routers, that they may have experience with. That is why I offer the links above to give you an idea of the relative performance differences in a real-world setting. Price usually has nothing to do with that aspect of consumer/prosumer equipment. The specific
model, does.
HTH.
