In Java Edition, you can use cobbled deepslate to craft weapons, tools, furnaces, and brewing stands. However, you can't on Bedrock Edition, which causes parity issues with Java.
MCPE-123669
Cobbled Deepslate cannot be crafted to tools/weapons/furnace/brewing stand
Resolved
Fixed
6
(Unassigned)
501666
Confirmed
Multiple
vanilla-parity
1.16.230.54 Beta, 1.16.230.52 Beta
1.17.0.50 Beta
Retrieved
This is a re-post of MCPE-123670