All of the above (Kowa YF; Opticron Adventurer, Vortex Diamondback HD) are worth checking and offer really good value. I really like the Adventurer, but I've had mixed experiences with quality control, something that I have not experienced with the Kowa (then the Kowa is more expensive).
Another addition to the list can be the Svbony sv202 ED 8x32, that can be had for around 90 - 130 €, depending on offers, and is just a mind-blowing achievement in terms of value, being probably as good as the Diamondback (if not better in many areas), but at half the price. However, it does not have the stellar Vortex warranty, which is something to consider, and also Svbony has been reported to also have mixed experiences when it comes to quality control. I bought an 8x32 recently and my unit is flawless. I think the level of sharpness and contrast on axis would probably please the OP, as well as the usability (nice and soft focus wheel, comfortable eyecups and armour, etc.).
As an alternative, as
@Elkhornsun mentiones, buying 2nd hand (which takes a bit of time, patience and, why not, a bit of luck) can yield great results. For 200 € I have bought things like a Monarch 7 8x30, which is a really very nice binocular, or the other day I saw a Kite Petrel 8x32 for less than 200 €, another really very good device. So it could be a good idea to check the 2nd hand market, both in your area or around here in Birdforum, or else in other sites where you can find trustworthy sellers.