2 months ago, bought a Q3 Max (TKL) + Q0 Max (numpad) combo, thinking to use them stock would already be fine (it was, but...)
2 months later, already spent hundreds on keycaps, switches, and stablizers lol.
The black set is JTK HSA white on black, a set of shinny finish ABS keycaps (also some metallic artisans)
The retro one is PBTfans Resonance R2, a set inspired by designer Dieter Rams.
Switch wise I am currently using Gateron Azure Dragon V3 on the alphas, since the Keychron came with Jupiter Banana which I liked, so upgraded to another early-bump tactile which a slightly heavier spring.
The mods are using Gateron Sylva (linear)
For stabs no matter how much I lube I couldn't get the stock Keychron stabs to stop rattling, so got a set of Gateron Ink V2 long pole stabs which are fantastic (hand lubed with Krytox)
Oh I also replaced the knobs with these that have PVD gunmetal coatings.
They weren't kidding when they say mechanical keyboard is a cash sinking rabbit hole...