A buddy of mine did the same thing years back, grabbed a cheap Linea off Craigslist for his cart and the steam was total garbage for like a month. Turned out the boiler was scaled up bad and the wand tip was clogged with old milk gunk, not a dead element or anything scary. He pulled the tip off, soaked it, descaled the boiler and it hit steam like new again. Rebuild kits for these run pretty cheap and there are a million videos on it, so I wouldn't panic yet. For $1,400 you basically stole that thing if the group head and boiler are solid, the steam fix is the easy part.

Check your microwave's manual before trying this because most of them say not to run it empty or with certain stuff inside, and a dry sponge is basically a fire starter. The real trick people miss is you need the sponge soaked, like dripping wet, not just damp, and you have to watch it the whole time. Also the whole germ killing thing only really works if the sponge is still wet when it comes out, because the steam is what does the work, not the heat itself. Once it dries out in there you are just cooking foam and fabric. Honestly a bowl of water next to the sponge works better and wont leave a scorch mark.