Ya, I been looking at all the bike pics seems everyone is doing either the corsa or the Continental Grand Prix 5000

And for good reason, I might add. If you're looking for max bang for the buck, I found that Schwalbe's Ones (a tad more durable) and Pro Ones (super fast but fragile) are often cheaper than Conti and Vittoria and are still on par with the best. Pricing might depend on your country and distributor, though. Same goes for the Tufo Calibra Plus. That's one hell of a fast and light tire, but a bit fragile. I'm based in Germany, so German tire brands are cheap here and so is Tufo, being a Czech brand (which is actually made in Czech Republic in contrast to all the others who are actually producing in the Far East).

BTW what tire set up is everyone using?

Vittoria Corsa all the way. Except for my tubular wheels. I’m using Tufo tubs in 28mm. They can be used with sealant and plugged like tubeless tires. So they’re very convenient. And despite Tufo having a bad rep for slow and harsh tires, I found that that’s a myth of the past when people were riding 21mm tubs at 140psi (if it ever was true). If you use them at sensible pressures they’re actually quite supple and not really any slower than my Cotton Corsas. Plus Tufo’s gravel tubeless tires are hands down the best I’ve ever used. In a sensible price range at least.

Yes. They're only selling off leftover stock. No explanation as to why.

I would honestly just expect no quality control whatsoever from velobuild.

Most if not all my Chiner (frame) parts had QC stickers on them somewhere. Whether that means that somebody actually checks tolerances or whether there's just some bloke applying them to make customers feel good - I don't know.
Anyway, I've not dealt with Velobuild in the early days - only started buying from them in 2022. But ever since then I have followed the VB threads here closely and they dealt reliably with all warranty claims from what I can tell - even if it takes a while sometimes. And since they do seem to respect their warranty and ship out replacement frames and parts, you would think that they're making some kind of effort at least to not have to deal with overly many of these issues.
Also, Chris told me that all their parts undergo testing according to the ISO 4210 testing protocol. However, providing documentation of ISO 4210 fatigue tests is obligatory if you wanna sell bike parts in most countries, AFAIK. No matter how cheap the stuff is. So that is not really a distinguishing factor.

But on the flipside, you will find plenty of horror stories of bad QC from the big brand's frames. This is the internet. People are very vocal here when they have issues. And very rarely are they screaming about it when stuff just works. Though this forum seems pretty balanced most of the time.

Damn bleeding these brakes is a mess. Front brake failed to bleed multiple times.
Saw a 105 di2 group cheap around me and bought it. With all the fails, I'm gonna sell it and be safe :s

Did you back off the tiny reach adjust screws in the brake levers when bleeding? They can push the master cilynder enough to block the oil flow when bleeding otherwise. You will still be able to push the oil through but with a lot of resistance and you won’t be able to get all the air out.

Hey guys how do you check pm with your indoor trainer, U use Erg for that? When I put my bike on my wahoo kicker in ERG training mode the magene pm shows around 10-15 watts less then kickr - so I need to put power slope in magene app at 105%. When I use it in normal mode then difference is not that big and power slope is around 102%. This is my first power meter and it is strange to me as all the reviews online say that pes p505 pm crankset is spot on. Any ideas what should I do? I did 5 spin backwards before measuring ofcourse.

Spot on compared to what?
You will always get somewhat different readings with different powermeters. You should decide what your baseline powermeter should be and then adjust your other device's power slopes accordingly. That's what I did. My Magene P505 reads less than my Favero Assiomas. I trust the Assiomas more so I adjustet my Magene to match them. My Elite Suito trainer is way off anyway. Since both my road bikes have power meters I don't even bother with the power readings that my trainer delivers.

has anyone ever tried these quick connectors for hydro lines? I've been eyeing these when building my bike up but ended up not using them.
But they could be a good solution. My bike has the hydro lines showing under the stem. You could put the quick connectors there and just detach the bars.