Did the companies tell you no when you asked them if you could share a previous project instead of completing theirs? From talking to many hiring managers, they also don't want to waste your time, and most will be happy to accept an alternative if it show similar skills to the ones they're looking for. I'm even seeing more teams offering this as an explicit option now.
There will always be a few who say no (IMO this could be a warning sign), but it doesn't hurt to ask :)
There will always be a few who say no (IMO this could be a warning sign), but it doesn't hurt to ask :)