Wait, you had a mechanical 10-12 years ago already? Cool. What kind? Some Cherry MX variant, probably?
What sort of switches do you like? Do you want something small, large, new, old?
Honestly, I don't really remember the exact keyboard but it was definitely something off the shelve.
Most probably a Logitech keyboard.
I just found out that there are different types of switches on keyboards - yeah, I'm really, really new to this.
I'm waiting for a Cherry MX switch tester to find out what I like. I have read quite a bit about the differences and watched some YT videos but feeling it myself will be the best way for me to decide what to go for.
I'm planning to get a 65% keyboard for a start. I definitely don't need a designated numpad and the F keys.
So far I narrowed it down to two possible keyboards: Ducky One 2 SF white or the Drop ALT.
I got a few questions on how to make things work. Is there a thread about how to connect a windows keyboard to a Mac?
Did Logitech make mechanical keyboards that far back? It looks like their first might have been the G710+:

It came out about 8 years ago. Looks like they usually had Cherry MX browns.
Personally, I would branch out from Cherry if you can. I don't think many people usually end up sticking with MX switches unless they got into mechanicals at a certain time and/or end up settling for their linear switches. They'll be a good starting point to figure out what type of switch you like between linear, tactile (though MX tactiles are not very tactile), and clicky but I think that most people agree that the grass does usually end up being greener on the other side of the fence. Personally, being a clicky guy myself, I really love Kailh's box jade and navy switches, for modern switches. Even those don't hold a candle to Alps SKCM blue or IBM's capacitive buckling springs for me.
I think 65% is about the lowest I could ever go as well myself. I have heard mostly good things about the ALT, and I have eyed one up repeatedly myself. I don't believe that the Ducky One 2 SF is hot swappable, at least from what I can find. The Drop ALT is, so if you did end up wanting to play around with switch configurations, that's a consideration to take. Soldered switches will always be more robust, but replacing them takes time, even with the right tools.
I'm not sure whether or not there is a thread of that kind. If there is, I imagine it would be buried in the Keyboards section somewhere. I have used plenty of non-Apple hardware with macOS/OSX, although I basically only use that operating system when somebody else needs help of some kind. I have yet to have encountered a USB keyboard that you couldn't just plug in and follow the pop-up prompts to allow the operating system to identify the layout. The legends may not match the key's purpose in macOS/OSX, but it should just work normally.
Most USB devices, especially peripherals, will work by default in macOS/OSX. I usually get a good laugh when people spend multiple hundreds on a $100 external hard drive because it is marketed to Apple consumers. Sadly, that's the only reason there's a market for such things. Ram, solid state drives (at least in systems that actually still have upgradeable storage), graphics cards (although Apple hasn't bothered to make drivers for certain groups of these), monitors, mice, keyboards, etc, etc. The vast majority of them will work without issue so long as the interface matches.
The reverse is also the case. Most hardware intended, for whatever reason, specifically for a Mac will work in Linux or Windows, provided that the hardware isn't something non-standard/odd, which is certainly more common with Apple-specific hardware.