Can't find falsetto. Only flageolet?

[Javier Real]

Hello
I am having real trouble finding my falsetto, I can't make that effortless sound, it is always strained.

I was always able to make a voice that I thought was falsetto, but I got to the conclusion that is flageolet instead. I got really used to it and it is relaxed, and really sounds like falsetto, but I think it isn't falsetto mainly because:
- It isn't connected to chest voice. I know sometimes it's difficult to connect head and chest voice, but this is extremely disconnected, it is a different world.
- I am able to transition smoothly from whistle to this flageolet. Not trying hard at all, just lowering the pitch from whistle, I end up in this voice. Demo: https://instaud.io/3rzk

So, an example of this strained 'falsetto', in a moment with the voice quite tired (so that the strain is noticeable): https://instaud.io/3rzm
Same song, in flageolet (I know it sounds a lot like a falsetto):https://instaud.io/3rzd
An example of a song, in falsetto, that sounded better, in a moment my voice wasn't that tired: https://instaud.io/3rzf (Yes, I like Ed Sheeran XD). This is as close to a relaxed falsetto that I can get.

So, any advice on how to find that relaxed falsetto? Maybe I am still unable to do it because I have those muscles untrained? I've tried yawning, making the sound of an owl, or Mickey Mouse's voice... Everything is strained. Any advice, or exercise?

Thank you in advance

Whistle to flageolet.mp3

Strained falsetto.mp3

Flageolet.mp3