If you already have DAC or digital audio player of some kind, meybe better look for separated amplifier only.
Like Fiio A5 if you want from Fiio. If it's available still.
You want the device to have like minimum 400mW per 32 ohms if you listen without equalizer and effects. If with, then min. 550-600mW (that's per 32 ohms again, as manufacturers usually post info for a 32 ohms power output) and above you need for a 250+ohms headphones.
If you find info for output power at 300ohms, look for above 120-150mW. 90-100 might be OK as super minimum.
Any device or amp will work really, its just that sometimes happens so that you buy something and then be like: aha, my phone is almost as loud as this. So for this not to happen and amplifier to be amplifier like it should be (or DAC/Amp you see mostly these days), don't look for underpowered devices is my advice.