29mm is ~35-40g lighter.

Sure. It's not twice (in my case, Cybrei cranks were even three times more expensive) as good, but it's still better. Considering that cranks are something likely to migrate from bike to bike, it's probably worth paying a bit more. By the way, based on the weight, you're most likely using the 29mm version, not the 24mm one. There isn't a significant difference in axles between the Lexon and Rockbros 24mm versions.

To be honest, the photos don’t provide much information. Without disassembly, it’s also hard to identify a specific differences. However, this was the first thing I noticed when I received the Lexon. I’ve had a Cybrei for some time now, and I also use a Rockbros on another bike. The Rockbros is much closer to the Cybrei and also specifies 50 Nm for this bolt. Both my Cybrei and Rockbros are torqued to 50 Nm. With the Lexon - this is just speculation, or maybe my eyes are deceiving me - the thread doesn’t seem as deep as Cybrei.

You know that weight of choice, when there's no urgency and you're just trying to find the perfect deal? Most Chinese frames either have a low stack or an extremely short seat tube in L/XL sizes. So I wondered if I'm probably looking at the wrong bikes...

I'm looking to buy an endurance-style frame for everyday riding, capable of running 32–35 mm tires on wide rims. I'm tall, and my body proportions require a very short reach combined with a relatively high stack, so most bikes I ride end up with a lot of spacers and a fairly upright position.

My current bike suffers from speed wobbles on descents, and despite multiple attempts by mechanics, the issue couldn't be resolved—so I'm looking for an upgrade.

Among many options, the Carbonda CFR-505 SL stands out as a near-perfect package (classic seatpost, UDH, T47).
I also considered the HongFu FM238, but the press-fit BB and limited 32 mm tire clearance are drawbacks.

I'm leaning toward giving the Carbonda a shot. Are there any other important things to know or other frames to consider?