At this point I think you are in the wrong scale for mortars and artillery for WW2. 1/32 has artillery and 1/6 has everything. Being a favorite of mine, I have mortars, heavy and light mg's, bazookas and artillery of all sizes. More modern stuff available is recoilless rifles (57nn, 75mm, 106mm).
New is a German mortar and TWO awesome Nebelwerfer's made by TWO competing companies (DID & Dragon). One might be metal. Same two companies are both releasing German motorcycles with sidecars.

1/6 guys are in heaven.
Can you imagine, such neat stuff by competing companies (more than the Sherman and the Mustang).
Sure would like to see more of this stuff in 1/18.
TTT
Sometimes I am the windshield, sometimes, I am the bug.