Zed has documentation, go-to definition/usage, local/remote debugger, can run/debug individual tests, has git and markdown. Essentially all the core IDE functionality is there. All of these work as well or better for Rust in Zed than IntelliJ.
ByteCode decompilation is a very Java-specific thing and I've not used Zed for Java yet. I suspect that they'll get around to it eventually if they don't already have it.
I've never used database plugins in any IDE I've ever used so I can't compare/contrast between Zed and JetBrains products. However, as soon as I see an IDE gain a database plugin, I know it's the beginning of the end for that IDE. After the database plugin is the CSS minimizer, the JavaScript Bundler, I guess the AI plugin is the new hip thing. For the twilight years of my IntelliJ/CLipn usage, the first thing I'd do upon installation would be to go remove all the damn plugins.