That’s my point. The 37 degree flare in a s/s braided hose end and most of the fittings for them are incompatible with 45 degree SAE flares. It’s a bit difficult to talk in generalities as I have to here. I think that adapters are available to go between the usual brake fittings and flares and the 37 degree hose ends but you need to the correct adapters. The flares can look similar but not be compatible.
I think often brake hose kits provide the adapters they expect you to need but you should make sure everything works together.
I may sound like an alarmist, but when people talk about SAE flares and s/s braided hose, I start to get worried.