I still use an IBM Model M keyboard every day, made in 1993. I'm currently looking for a new keyboard that takes less desk space and doesn't require a PS/2 adapter, but the Model M still works fine and is a pleasure to type on.
Keyboard rant: I'm appalled that it's so hard to find a good mechanical keyboard that is not meant for gamers with those RGB lights. Part of the problem is Europe, some options either don't get here or are usually out of stock. But even looking at the total market there are just not that many mechanical keyboards with quality switches, a simple backlight light and a USB hub with a couple ports in the keyboard.
If you're a fan of the Model M then you must know about Unicomp[1]
ergodox that usually put out a split ergonomic keyboard have recently released a cut down keyboard called the Planck that might interest you[2]. But to go from a gigantic beast of a keyboard to such a wee thing might be daunting.
The /r/mechanicalkeyboards dwellers might be able to help you out as well[3] as well as the mechanicalkeyboards website[4]
FWIW I happily used a Filco Majestouch for years before switching to an 'ergonomic' keyboard (ergodox). The Microsoft Ergo Sculpt is really good for me as well, I still use it on my secondary desktop.
I actually asked in /r/MechanicalKeyboards, but they didn't help much, just pointed me to Unicomp but that's not what I'm looking for as it's basically the same size as the Model M. It looks like Unicomp will be releasing a "Spacesaver" Tenkeyless model in the upcoming weeks [1], that might be an option.
The Filco Majestouch 2 Ninja TKL [2] is one of my top candidates right now, or a Ducky One 2 TKL [3] variation. I actually tried to get both in the past weeks: the Filco couldn't get shipped because of COVID-19; and the Ducky One 2 ran out of stock (the European market problem I was mentioning before). Very frustrating.
About ergonomic keyboards I don't want to go through the pain of relearning how to type. I have been typing on the Model M for 25 years now and my muscle memory is deeply engrained, I want a layout that is as similar as possible (so 80% Tenkeyless).
The Planck seems unnecessarily small to me. I'm not moving my keyboard so the absolute smallest size is not a requirement, I just want to get rid of the numpad to have the mouse closer.
Instead of Ducky One 2, I would look into either Varmilo or Leopold. Similar design, better quality and in the case of Leopold its very understated, no RGB and game-ry branding.
I have heard good things about both Leopold and Varmilo, but they are even harder to come by than the options I mentioned. I have to compromise for a keyboard I can buy in the EU (but with an US layout).
At least motherboards typically have a BIOS option to turn that off. For other components you better be using Windows if you don't want your computer to barf colors all day.
Buckling springs are my favorite but I also prefer tenkeyless. I'm currently using a Realforce 87. Topre switches aren't as stiff as buckling springs but have a more similar feel than other switches.
As for keyboards with lights, you can turn the lights off.
The outgoing HHKB Pro2 might interest you if it's within your budget. It's hard to find now as it's been replaced by the HHKB Pro Classic with no USB hub.
I know HHKB are good quality, but I'm looking for a Tenkeyless (i.e. without numpad) keyboard, my muscle memory is too ingrained by now I fear.
Also pretty ridiculous that the two USB ports are mini USB.
I don't really have a budget if I could find the right keyboard, but after searching extensively there is none that checks all the boxes. Either I need to give up the USB ports, go with full size or go with lower quality (Das Keyboard).
You are right, the image on the website is just very small. The input USB port is the one that is mini-USB, probably for durability reasons (microUSB breaks easily).
Keyboard rant: I'm appalled that it's so hard to find a good mechanical keyboard that is not meant for gamers with those RGB lights. Part of the problem is Europe, some options either don't get here or are usually out of stock. But even looking at the total market there are just not that many mechanical keyboards with quality switches, a simple backlight light and a USB hub with a couple ports in the keyboard.