I recommend this spool holder for the S2, it works great. You pull out the rollers and it fits right in.
I never ended up printing the PTFE Holder in the other link, I just run the Bambu PTFE from the Bambu 4-in-1 PTFE Adapter to one of the holes at the top. I feed it through the plastic tube already in the hole. I position the spool so the filament goes from underneath the spool than up into the top hole rather than feeding it over the top of the spool. The path seems less restrictive.
I’ve used it with TPU-HF a few times, I keep the heater on while using it.