Long story short - my a4tech x7 is slowly dying. Its not a big deal, since I've bought this mouse years ago, back when I've used to be a windows user (since there is simply no way to configure its additional buttons under linux). But still - Im looking for a replacement.

At the very beginning, I thought about roccat's mice. Since there is a whole project about a custom configuration software under linux for them (and roccat tyon simply looks like a freaking helicopter's controller). But then I've faced that their products arent available in local shops of my city. If nothing else, I still can order it over net, but... its not something, I really want to do if there are any viable alternatives.

Speaking of critical points, there are 3:
1. Be wired. Yes, thats what hurts my current mouse the most. Yet its simply unsecure to use wireless mice outside of home.
2. Feature at least 3 additional buttons. May sound minor for most of people, but since Im arpg fan, its kinda important (I dont use mouse outside of gaming much anyway).
I also REALLY love the placement of one of extras on my current x7 - near one of main buttons, extremely accessible. But its not that important - I may re-learn, if necessary.
3. Be configurable under linux. Thats the main issue. I dont care if its done by third party project, or official software, however.

Overall - any suggestions?

Good luck. I have never had a good experience getting anything to work with Linux.

I love Kensington mice and trackballs, but they're generally only listed as plug and play with Windows.

My Kensington Expert Mouse is awesome, but yeah, I would love to be able to configure the 4th button on it, that button is rather unusable as it is (I think it sometimes works as "back" in web browsers, or maybe "go to the address in the clipboard", and more often than not it's annoying when I accidentally click it).

interesting, didnt hear about this project

I can recommend Zalman zm-m600r, it has hardware sensitivity and polling switches, although its led sensor maybe a bit dated.

Not aware of any with official Linux support, and for Roccat the unofficial stuff, with issues, seems to be only for the old drivers, so up to Tyon. Everything that lists Swarm, so Nyth, Leadr (but that's wireless), Kone AIMO, Kone Pure SE and Owl-Eye, Kone EMP, Kova, Kova[+] and Kiro, probably doesn't even have an unofficial Linux version.

But mice that store everything on board should be manageable if you have a Windows install to make the settings and don't rely on stuff that's done through the software. When I used Linux for a few weeks in 2016, I still used my Kone XTD, with the settings it had from Windows, didn't even try the Linux driver. And seeing as Swarm is completely unusable for me due to starting a bunch of processes and constantly tracking all I do and eating 1-2% CPU for that and for the AIMO lighting even if I have both monitoring and AIMO lighting off, since I got the AIMO at the start of the year I'm using it on Windows without the software, just created profiles and started it a couple more times since to modify some stuff, just save and exit. Plenty of the functions added in Swarm, compared to old drivers, won't work without it, but still have what I was used to on the XTD, minus automatic profile switching. But since on the AIMO I can trust the wheel more (on the XTD I'd usually get middle clicking or scrolling too if I tilted it, so disabled tilting), I have shift+tilt for profile switching.
After all of that, careful with reliability. On any brand really. But on the XTD the first time the wheel failed after a month, and after a bit of a mess with the warranty the replacement worked fine for a year and 3 months, then started double clicking, at first not... reliably enough for me to dare to send it in again, then warranty expired and it soon became next to unusable, though I still struggled with it for quite some time before replacing with this. Tried to open it and try some of the fixes I saw online, but one screw was completely stuck and couldn't do it.

Oh, actually see here about the end of support for Linux, from the guy who worked on that for Roccat mice.

Maybe another A4TECH X7? There are several models under the X7 / Oscar name. I've used a few o them (XL-747H being the best, using it for 4 years with no problems) and I love that button between the left click button and the scroll wheel. Unfortunately I haven't seen something similar on other mice, apart from A4TECH or clones of them, like Sharkoon FireGlider. Most of gaming mice have buttons on the left side of the left click button, but I find them extremely uncomfortable to use.

Now I use a SteelSeries Rival 500, which I love it, having 6 buttons on the thumb area, but it doesn't have official support for Linux. Maybe in this thread you'll find something useful.

Some mice that caught my attention with their side buttons are Trust GXT155 and Redragon M902 Samsara, but I didn't test any of them. Same goes for FUNC MS-3, which might not be produced anymore.

What I never tried and I'm curious a bit, but I don't think I'd like it, is one of those with 9-12 buttons on the side, like Corsair Scimitar, Razer Naga or Roccat Nyth. In case you'll want to try your luck with something like this, there are some cheaper variants, like Trust GXT 166, Redragon M901 Perdition, Redragon M908 Impact and Redragon M990 Legend.

The best mouse reviews, I've found to be on this youtube channel. And here is a sensors list.

none of them are configurable under linux and windows tool require admin rights (so wine wont help either) :/