You would be doing very well to get more than about an octave or so of useful transmit power bandwidth out of a piezo or piezo composite transducer.
The usual approach is to use a tuned transformer right behind the element to provide both voltage step up and to tune out most of the fixed capacitance, then back this up with an L or T network (with series resistor to kill the Q and limit the misbehavior at the band edges).
The general approach to power amplifiers is to design them to drive a low impedance (which is potentially highly reactive, SOA is a real issue) to a hundred V or so, and then to design a match for whatever transducer you are using to suit.
I think that if I was trying for an amp that could adapt to different transducers automatically, it would include an impedance bridge and relay switched L network at the output.
2KHz would be a rather large tonpills or free flooded ring element which is a somewhat specialized thing often used in arrays for applications like sub bottom profiling, most civilian transducers are resonant a decade or so higher then that.
Here is what a fairly typical omnidirectional broadband transmit element looks like Neptune sonar D11-BB note the two spikes on the admittance plot that pretty much define the edges of the usable bandwidth, note also that the broadband devices usually have a thinner piezo ceramic and so are less able to cope with large voltages.