some embassies might want accommodations for your entire stay but they will tell you and let you add as needed, in which case just book something cancellable
i emailed with the NY embassy and offered to send them my last trip, over 30 hotels across 8 provinces and mentioned Phuket was currently having flood warnings at the end of November and they just didn’t care
Having a short term visa showing proof of leaving isn’t the craziest request. Needing to show full booking confirmation for 2-3 months is actually absurd, especially given the severe weather that impacts many regions.
Onward tickets and fully cancellable booking confirmations to satisfy the requirements