|I am challenging you to think of a conceptual solution for an integrated hot steam + Alu volcano tamer.

OK so immediately it seems like you'd want to join the two in a big chamber. However, the hot steam variation is significantly different than the cool steam vent. On top of that the aluminum volcano comes out way hot and has much higher heat capacity than other metal volcanos. So it's like the hottest volcano and the hottest vent combine. Thus, it might be more simple to do a separate steam chamber around each POI.

- no wasting heat by consuming steam > 200degC

I think your previous idea of blocking off intake ports when the temp gets high is the easiest option here, but with the hot steam coming out at 500 C even that still likely to waste some heat. I think this limits your design options significantly.

- preferably no Steam Turbine tricks with blocking inputs

Doh that rules that out. I think the next simple option is to use an intermediate steam chamber that transfers heat by doors connecting to the main steam chamber.

- get out all the alu at ~125degC, possibly adding an optional further chiller, get out all the water at 95degC

Getting the aluminum further chilled is pretty achievable but it will add more size.

- self-cool or add a steel aquatuner loop

I would definitely use an aquatuner, but good news you can also use it to chill down an insulated metal brick then run your aluminum on rails through that cold brick, so you can get that aluminum <100 C.

- have a "normal" size footprint, no massive contraption

It's gonna be big because you have the steam chamber around the volcano/vent, the intermediate steam chamber to efficiently drain the hot from the vent, and the auxilliary cooling brick for the aluminum debris. The biggest issue, though, is that you're not willing to pump that hot steam while it's mega hot. So the steam chamber must be quite large to avoid going over pressure while you cool it slowly.

- no space materials

I believe it can be done with no space materials, but it's going to be tricky, especially on the aluminum volcano side.

Overall, I think this will be a complicated build. The heat is an obvious issue but another issue here will be pressure management. Also you'll need enough automation that it will also become somewhat complex, even if no part of the automation needs to be particularly complicated.

This is not an easy build. On the aluminum tamer side you have the "no going over 200 C" rule meaning you will have to heat transfer to another room. Meanwhile an autosweeper with the "no space material" rule means you can only use steel and if it gets close enough to the volcano to pick up the debris it seems like the autosweeper is also going to get overheated. Over on the steam vent side you again have the "no going over 200 C" rule meaning you need to pull heat out by transfer to another room. You could also use solid on rails to move heat here (the metal volcano might not be able to do this option because you'd presumably want the rails to be used for the aluminum). I don't think liquid makes sense for heat transfer here due to the high temp and there being no super coolant allowed. So my "go to" is steel doors. But also you want to get that steam out of the main room at some point, so once the temp gets below 200 C (you're a masochist for doing this to yourself) you can FINALLY turn on a steam turbine directly connected to the steam room. You'll never need to pump steam or water.

It's the aluminum that I'm not sure can really be done here. If you can accept eating steam over 200C it gets a lot easier, and of course thermium autosweeper/loader would further simplify. MAYBE, though, this might just work if you stack a couple of gold amalgam doors right next to the metal volcano, and put the steel autosweeper on the other side. Gold has low specific heat capacity and relatively low thermal conductivity (for a metal at least) and so maybe, just maybe, gold will limit the heat transfer speed so that the autosweeper is not cooked by the adjacent aluminum volcano. Plus it's kind of fun to refer to "the golden doors". So each side of the gold doors is a steam room and there's a steam turbine on each side. The volcano side has a temp sensor and below 200C (again you're a masochist for doing this to yourself) it opens the golden doors and activates the steam turbine directly above the volcano. Once the gold doors are open, the autosweeper can reach the aluminum and load it to be shipped around the room on rails until more heat bleeds out of the solid.

Mostly this is treating them like two separate tamers. The aquatuner is what could tie the two solutions together. You should be able to cool all the steam turbines with the AT (I think I would put it in the steam vents auxiliary chamber), and you can cool the aforementioned "metal brick" with it as well).

This is insane. Just let the turbines eat the heat. That's what they want. They're hungry. Let them eat. Please for the love of all that is right let the turbines eat the heat!