I mean if you have a significant chunk of free cash sitting around there's almost no reason not to put a portion of it in 3-6 month Treasuries or something.
The return won't be much but it's better than letting the cash sit idle and evaporate due to inflation
Depends on the funding vehicle. If you're on a SAFE, and still a going concern, then I think returning investor funds would trigger a priced round and you'd end up converting at a (hopefully) high valuation
The return won't be much but it's better than letting the cash sit idle and evaporate due to inflation