It isn’t that simple, but since you are asking a simple question then I would answer, that every new generation DAP are very powerful. On the not so simple side of things, it is the matter and relation between voltage swings and current output vs output impedance at specific load and of the industrial standard of 1000Hz...which can lead down a rabbit hole real quick
SP2000, Dx220+Amp8, Cayin N8....etc...
transportable : Kann Cube, DMP-Z1 which has 1.5W + 1.5W on high-gain
under $200? Not sure, but if under $400 then I would recommend DX160