I am going to apply, but currently looking for a cofounder[1] after my previous cofounder left. Is it advisable to wait until I've recruited a new cofounder to submit the application?
I'd probably wait until the application deadline, but if you don't have a new cofounder by then, I'd just submit with what you have.
It's true we're a little less likely to accept single founders, but it's only one of many factors and the probability delta not that large. Particularly if you are a technical founder, which I see you are.
[1] - https://angel.co/imersme/jobs/386205-co-founder details about co-founder position (sf bay area) if anyone is interested. Reach me at "me" at my website (in profile) or reply here.