Looking at your title, then reading the text in your OP,
vanadium
, it seems you're not looking for a small knife but a smaller-shop maker. That would keep most Shirogorov offerings out of your price range, though some can be had off the secondary market for under $600.
A larger Shiro you might find on the Exchange for under $600 would be the Hati, which has a 95 mm blade and runs on PB washers, making it more like a CRK with a flipper than their other models which run on BBs. I got mine as a user here for $525. It has a bushing pivot like a CRK 21 and the same hydraulic smoothness. It flips well enough, though not quite like a BB knife, and its M390 blade is an excellent slicer.
Definitely under $600 new would be the NeOn Ultra-lite with S30V (some were available with Elmax, though they seem to be out of stock currently). This is the open back version of the usual NeOn Lite that goes for $550 new. Mine came LNIB off the Exchange for just under $500 and is a 3.25" blade that should be more generously hand-filling than a small Sebenza. The regular NeOn Lites have M390 or S90V and are $650ish new if you can buy one right and can be had for under $600 on the Exchange.
I have 6 Shiros and highly recommend them in every aspect.
I know you don't want to debate, but I find Hinderers to be very high quality for F&F, materials, design, and superior feel in hand. I've bought 5 and kept 4, only selling one for greater variety and not liking its coated blade and slabs. The knives do have a deserved rep for inconsistent detent/flipping action, though Hinderer has reportedly dialed that in better lately. My 4 vary from OK to very good and I have no issue with Teflon washers, all mine being extremely smooth with no lack of sturdiness.
I put my Hinderers right up there with my CRKs and Shiros for quality.
One more to mention is the Olamic Wayfarer 247. Mine is a very base "Stealth" model with stonewashed PVD coating on blade and slabs and gold-anodized hardware that came in just under $400 new. Excellent M390 blade shape and sharpness, strong detent/flipping action, great in hand, super F&F. A really nice touch is the detent-ball ramp cut into the blade tang for hitch-free closing. Eugene at Olamic is highly communicative and their customer service is reportedly excellent. Depending on how much bling you want, the price range there is $400-600. I think my more modest version is one helluva looker and a super value at the price. Highly recommended!
Sorry for the wall of text--guess that's way more than 2 cents worth.