This is possible using Access Rules, documented at Intro to access rules - Grist Help Center.
For what you ask, it may be enough to create a rule with a condition like user.Access != OWNER and set permission to “Read-only” or “None”. This can be added on a table level, or to a list of columns within a table.
Access Rules are a very powerful feature! But… not easy to use (we are hoping to make it easier and more intuitive over time). I recommend reading that article, and asking here if you run into difficulties.