Good ideas to get more attack above.
Using other methods like multiband compression, you can really create some hyper pushed sounds - just depends on your demands, system and so on. In a DAW you can push and pull anything in any direction but also risk losing some realism a little easier than tweaking in Pianoteq.
If just in Pianoteq, I'd suggest that instead of using compression, try without it - less 'flattening' possible - the perception of attack with a lot of compression can be sound false or shaped when you get used to hearing it, and also you might want to turn off the limiter.
Next, try turning down the main volume -15 or so (and/or the 'level' inside the effects section - or mic levels if balancing them up) - the next step is of course maybe needing more volume by raising your sound system volume instead (depending if recording/playing etc - adjust to your ears or your audio systems' level indicators (For example, in an outboard audio unit, you might have volume in and volume out - balance these until it sounds good, not too hot if recording if poss) - etc - it's going to be different for different situations).
Some reasons and extra things to do:
There's a lot of dynamic range to be had in Pianoteq - it's emulating a beast of an instrument - and if anything, to really get bite, you could do the above for better results rather than crunching and falsely boosting transients (might be OK of course) but in order to get the cleanest signal and greatest dynamic range without pushing limiter into the red, this can help. You are outputting now the most natural shape (wave as viewed in an audio program). Instead of a fat and flat waveform, you'll see a more detailed one. Those peaks and troughs are what you want to look at, they represent your dynamic range from soft to loudest.
From there, as suggested, all those other things like EQ etc. will be more likely to sound more realistic when applied.
(I've posted about the next paras before more than a few times so will try to keep it short)
When I tweak a Pianoteq sound in a DAW, I often like to use more than one instance of Pianoteq. There's no correct things to do but maybe consider very subtle things like making track 1 'normal-ish' and the same preset on track 2 but with way less volume, way more reverb (distant), stereo expanded maybe and heavy EQ and other things to make it sound like wide real room reverb - mix it way down low and bring it up until you notice it, then drop it down a few dB.. add another Pianoteq track with really loud hammer focus and EQ for that.. again, mix it up until it stands out, then drop it a little - with some time and effort you can create quite interesting sounds of your own.
These days though, Pianoteq's default presets are so good, with just a little alteration in Pianoteq you should be able to pull a sound you'll be more than happy with. I basically haven't felt the need to embellish things in a DAW for a while now - I'm basically happy to work mostly without using the DAW for extra shaping - only if making modern music where I don't focus on the piano's realism. Pianoteq is exceptional for creating unreal sounds also which means even less time in the DAW which has been a goal for me for some time, so I'm sure you can push Pianoteq to give you some maximum crunch without too much fuss.
Definitely, you can get great brightness with multiband EQs but maybe attack can be worked on within Pianoteq best. I find the best outcomes I have with tweaking for my tastes is by making probably best described as 'logical' small tweaks to as many things as possible in Pro. Like, hammer hardness as mentioned then a lot of dynamics (mix these with other changes, like to damper settings, unison width, impedance, Q factor, pre and pos EQs and maybe get up close with note-edit to make changes to individual notes' loudness etc - you can draw lines across the range from left to right covering all the keys, or do more painstaking edits to individual notes to help these sing (esp if your song benefits from a few louder strings etc) - all really helpful for making the piano behave exactly the way you want.
Hope some of that makes for some good results - best of luck
Pianoteq Studio Bundle (Pro plus all instruments) - Kawai MP11 digital piano - Yamaha HS8 monitors