Add another datapoint to the list:
Booked ticket for business trip in March. Trip cancelled for obvious reason. I thought I'll just leave the ticket as open since SQ is offering incentive for rebooking later.
However, SQ has not increased their flights/routes and has no indication to do so in the next few months, plus SIN is still largely closed for transit, I decided to ask for refund.
Filled out the form on Aug 17, a few back and forth email and the refund process started Aug 21. The refund was deposited into my credit card on Aug 26.

Overall, really happy with the process and time to resolution.