On Android it's possible to do it via the developer options.
Settings > System > Advanced > Developer options > Bluetooth audio codec
If you don't see the "developer options", google how to enable them. It's easy, so don't be afraid ;P.
I should have been more specific .. On my Galaxy Note 10+ in Developer Options I do have the Bluetooth options that allow me to force the codec.. But unfortunately Samsung only offers APTX, not APTX-HD..
On my FiiO M15 however, I do have the Developer Options enabled but there are no Bluetooth settings in there, potentially due to it being an Android 7 device... The M15 however does support both APTX-HD and LDAC..
So I was hoping for a setting similar to FiiO NH3 NC that allows to enable/disable codecs individually on the cans itself..