I have created a text object and selected Extrude from Effects but all x & y mesurements are greyed out so can't set extrusion. It is Arial text selected
Convert it to curves.
No that didn't work either
Please post a small file that does not work for you. I'll mess with it.
https://1drv.ms/u/s!Aqts-m6HGagqnO0tOe1T0Yis_vAtvw?e=LbPijo