My 98 S70 T5M (same powertrain as yours) has the exact
same notchiness (I mean I would describe it the same way).
Much worse when cold. I seem to be able to feel the thing move
through a "valley" and then into gear.

I have a 1/97 build date (it is on the door) on mine and 43K
miles.

There is a TSB that the dealer might know about. It applies
if you miss shifts (they flush the clutch and replace some
parts). I assume it is because the clutch is not completly
disengaging. My dealer offered to do this for free last
month when I asked to see a copy of the TSB but I decided not
to do it since I don't really miss shifts and I kind of
operate on the don't fix it if it ain't broke idea. I have
a copy at home and can post the TSB number if you are interested
(again, only applies if you miss shifts).

Oh, TSB is Technical Service Bulletin which are additional
repair instructions for common problems (helps the techs get
through these problems faster and helps them identify them).
They are not recalls.

I also bled my clutch and that helped a bit with the feel.
This was a bit tricky but a garage could do it easily enough
if you don't have a power brake bleeder.