Mechanical Keyboards

To use? Sure, though I'm not sure it would be any better than an offbrand low-profile mechanical you might find for ten or fifteen bucks cheaper.

To configure beyond the default layout? No. Apart from a handful of models that have been ported to QMK by third parties, Redragon boards have to be configured or re-mapped in windows. I have an E-Yooso that's a pcb-twin of a Redragon, and the RD software is fine but not very flexible and, as mentioned, windows only.

This is not to say it would be a bad board, far from it compared to an average cheapo membrane board, just that there's not a lot of unique stuff going on with your average floating-keycap gamer board. I do find I personally don't care for the choice to lose the 13 keys of the F-row in favor of ten rubber circles that do the same thing, only slightly worse. I am a fan of roller encoders versus standard vertical knobs, but IIRC the software may not let you customize the inevitable volume and lighting controls mapped to it.

personally: only second-hand info about reddragon keyboards.

The pricepoint is low, don't expect premium experience. It'll do keyboard stuff just fine, most likely.

Also, apparently the customization app doesn't work at all on linux, even through wine. EDIT: openrgb does support some reddragon models, but only mice. https://openrgb.org/devices_0.9.html?search=red+dragon - but, keyboard support might happen?

I tried out 4 different Redragon mx keyboards in the last year. They're fine for what they are, and I am not a huge gamer, but for that truly satisfying typing experience, I did not find them enjoyable. I didn't try the 609 SE, but I did try a low profile full size Horus, and the typing sound and feel are garbage.