Any fake transparency shader will be limited to static cubemaps without modifying the engine to get access to the reflection probes, and they’re buried in there deep. I tried to find a way to dynamically write custom ones for a different purpose, but the system is so obscured that I couldn’t really follow it.
For a simple solid glass object sampling a static reflection map, something like this should work. The cubemap needs mips baked to be able to modify the blurriness.
