There’s plenty of slash-resistant materials on the market, but are there any stab resistant fabrics that could be worn just as comforta

Shear thickening fluid isn’t very stab resistant, particularly to a spike like an ice-pick. You probably want metal plates. A soft backing for the vest will reduce the stabbing force.
Bulletproof vest – Wikipedia
from the article above:
Stab and spike armor standards have been developed using 3 different backing materials. The Draft EU norm calls out Roma clay, The California DOC called out 60% ballistic gelatin and the current standard for NIJ and HOSDB calls out a multi-part foam and rubber backing material.
Using Roma clay backing, only metallic stab solutions met the 109 joule Calif. DOC ice pick requirement
Using 10% Gelatin backing, all fabric stab solutions were able to meet the 109 joule Calif. DOC ice pick requirement.
Most recently the Draft ISO prEN ISO 14876 norm selected Roma as the backing for both ballistics and stab testing.
This history helps explain an important factor in Ballistics and Stab armor testing, backing stiffness affects armor penetration resistance. The energy dissipation of the armor-tissue system is Energy = Force × Displacement when testing on backings that are softer and more deformable the total impact energy is absorbed at lower force. When the force is reduced by a softer more compliant backing the armor is less likely to be penetrated. The use of harder Roma materials in the ISO draft norm makes this the most rigorous of the stab standards in use today.

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