Best dummy tickets websites for Schengen Visa?

I’m in the process of applying for a Schengen Visa and I’ve hit a bit of a roadblock. I know I need to provide proof of a return flight but I’m not ready to actually book my flights yet since my plans might change. I’ve heard that getting a dummy flight ticket is the way to go, but not sure which websites are reliable for this. I don’t wanna risk using a site that might get me in trouble with the embassy. Has anyone here applied for a Schengen Visa recently? What’s the best websites for getting a dummy flight ticket that’s safe and accepted by the consulate? Any tips would be super helpful!