can i do it or does it just not work that way
As opposed to the normal fruiting bag
If it is possible, do I have to use a different substrate so it would hold up? Thank you.
The problem you will have is huge losses of humidity resulting in the substrate drying out. If you are trying to avoid using plastic bags you could use buckets or containers instead.
Shiitakes require 85% humidity for pinning and fruit development, where as Oysters require 95% which is why plastic bags are unfortunately used because when they cut the bag mushrooms are provided with fresh air exchange + tons of humidity (between the plastic and the surface).
So, I went and googled, and indeed "oyster mushroom log kits" are widely available, implying that using a log works fine with them as well.
Of course, the "log" process has differences from the "bag" process in handling and management, as you have an exposed log not a mostly-plastic-wrapped bag of sawdust. Moisture management is the big difference.
Some refer to log sections as "wood rounds" or "rounds"