There are a million opamps out there and there's a reason there are a million opamps (something I've slowly come to appreciate) and it's because every specification matters for a given application.
So to help we'd need more details like signal bandwidth (not necessarily related to sample rate), voltage range, power requirements, application temperature range, input impedance?
There may be other system level options too
-Can you periodically switch out/short out the measured signal to record and null offset? If yes then amplifier offset isn't important at all
-Can you record and store (flash) initial offset during manufacturing? If yes then offset drift is all that matters
-How wide is your operating temperature range? If its narrow then 1mV of offset is quite easy for non chopping amplifiers