Ipad 10.2" for a PhD: 32 or 128 GB?
As @benwiggy pointed out correctly, storage always tends to run short.
Of course, such a topic is a matter of personal opinion. Trying to keep objective, please consider the following:

The 32 GB option is the &quot;entry-level&quot; option—in fact, no other iPad even offers such a low option anymore! (iPad Air and iPad mini start at 64 GB; iPad Pro at 128 GB.) It is safe to assume that it's on the market solely as a cheap entry model to the Apple universe.
Getting the model with more storage will, even if you have no use for it now, increase the device's value down the line. I, for one, tend to sell my old Apple devices (usually after upgrading to a newer model): the resale value of a 32 GB devices will be considerably less than the same device with 128 GB.