We are all, regulars on this forum, field testing.
When we have a new Sfos device we all report the events along our journey here in the forum. You can do it too. But noone will sponsor you with a 699eur phone for that, i can guarantee you.
Nevertheless, as earlier suggested, just get a Sony Xperia. Here are the models supported: Supported Devices | Sailfish OS Documentation
Flash Sfos on it. We call that program Sailfish X: Sailfish X Installation Instructions - The Privacy Respecting European OS and AI Solution Provider
And then have fun 