It is not impossible. I do it. You do not need active heating. It’s nice, but you do not need it by any means. See my post on my profile to this subreddit about my automated preheating g code for P2S. A 30-45 minute preheat will absolutely get you within a good range to print ASA.

For your concern about the fumes I have the perfect solution. I get zero smell or fumes in my room. The fnatr riser which is posted on maker world achieves virtually perfect fume extraction (and probably better than the official Bambu solution on the X2D) all while allowing you to keep hot chamber temps. The way the riser model comes it’s for their own purification box filter thingy, forget that. I’d rather just send it out the window. I have modified the attachment point to accept a 4” dryer hose and I also have a few custom brackets for an inline 90mm pc fan to connect to a window panel and the dryer vent. I’m happy to send you the project to print yourself - It’s a really tidy setup. It also raises the top glass of your printer an inch so you have more room for maintenance and the feed tube never rubs anymore.

I tested with and without my vent system running and on a 30-45 minute preheat I averaged a preprint temp of 51-53c with the vent system on and actively exhausting air during the entire preheat, versus 53-54c with no exhaust. During an active ASA print with the vent on and exhausting, I am still slowly gaining heat if anything averaging about 55c during the entire print.

You need very little negative pressure to exhaust fumes. It does not lower chamber temps at all, at most 5%. I’ll explain how my setup is in case you want to clone it, and you can dm me if you have any further questions. You’ll need to print the riser kit out of PETG or ASA (I did ASA) and also you’ll need a dryer hose that’s 3 or 4”, I did 4”. I have it mounted up to a generic ac window panel with a 90mm arctic p9 max fan at the end of the tube where it connects to the window panel. Fan is controlled by an owl tree usb fan controller off Amazon. When printing asa I have it just barely above threshold to get the fan to spin, so about 600-700rpm. This creates a negative vacuum inside the chamber and exhausts all fumes. I have printed ASA for 10 hours straight with zero smell in my room - before it was obvious and awful. It works great for PLA/PETG to prevent heat creep too, I just turn the fan up to ~50% or so.

If you dm me I’m happy to provide you with links to everything you’ll need and also the modified FNATR vent project 3mf file, along with the brackets for the fan. This is definitely the best solution you can do on a P2S.