Netjets / Flex are fractional, so you can't just charter a flight to my knowledge. Planet 9 was formed in 2018, so not much of a track record to judge.
The only one left that you've listed is VistaJet - you'll get a great experience with VJ, but unlikely to get a good value / bang for buck (depending on dates / routing / one way vs RT, etc).
You seem to have an aversion to managed aircraft, but that's likely where you'll find the best value (without compromising safety, experience, or really anything else - just requires more work/knowledge). There's a reason there are extremely few fully-owned fleets.
If you prefer, PM me and I'm happy to help 1:1.