This doesn’t answer why it’s not working when the curve is set on your transmitter, but…
I’ve always just set up my throttle expo and midpoint in betaflight rather than in my transmitter (first half of the video below). Given that the hover point will vary on each quad, it makes more sense to me to do it this way.

I tried to do this a while back and gave up. Instead I did something similar by setting throttle limit and changing the type to scale which gave slightly better stick resolution and made it slightly more linear. before that it almost seemed to be like the first 25% on the stick was linear, then the other 75% was almost a straight line up, so after 25% it was rocketing towards the moon at full power.

It's on my list of things to explore again at some point. The other is tuning rates.

Did you assiging the curve you created to channel 1 on the mixer page replacing throttle ?

I have 3 different throttle curves on the left 3 position switch on the tango. (only needed a lineair offset so i have a 100% 85% 70% limit on a switch)
Did not create them on the curves page but directly on the inputs page under a free input (I12). Then on each of these activated or not based on switch position.
Then on mixer page swap ch1 from throttle to my new I12
Done

i does prefer throttle curve over betaflight

aaaand I think I have it. I went into the OUTPUTS page of the radio and selected edit on CH1...I can select the curve there and BOOM - I see the proper output from the radio now! I need to test fly, but this appears to be a needed step..doesnt seem like the curves and mixes page does much for what signal is output, but the outputs page made the values move correctly for betaflight

I need to do this. I have Frsky TX and the throttle gimbal has notches. one partcular notch and it sinks, and just one notch up and it ascends like crazy...
I wonder if a little expo is all I need as well.

Aaaaand NOPE! I am about at my wits end. Ill post the pages from the radio tomorrow to see if someone has some insight...

                So here are the screens from the Tango2.  It all looks like it should work to my, but the quad acts like its simply flying off raw stick position from the transmitter no matter what I change.

Thanks!

Thanks all - with your help here and the TBS Lounge I figured it out.  Radio was in XF mode 2, and I used the default mappings when I created a model so that made things work-ish BetaFlight.   It also made things REALLY weird once I put the radio in freedom tx mode.  Once I changed my channel order around in betaflight and only had the curve in the mixer screen on the radio things are good to go and the throttle curve works when set in the radio.  Never paid much attention to the radio channel assignment when setting up a new model, and it was NOT in freedomTX mode...I learned something today!  

For those who say to set the throttle curves in betaflight, can I ask why?  I am used to programming the radio, as I can make changes on-the-fly with the radio but need a laptop to change BetaFlight.

To summarize, the radio was in XF2 mode which is just a pass through.  By changing the gimble output to freedomTX the curves in the radio now work as advertised.  I had to do a weird channel mapping in betaflight, but I will set-uo the radio again sometime soon with default mappings of AETR or TAER, but its flying and doing what I wanted it to do now.  Last question - radio defaults to TAER - why is AETR the default in Betaflight?

THANKS!

AETR and TAER are the two most common channel maps, my best guess is that they had to pick one.

Regarding setting curves in betaflight, speaking for myself:

I don’t set up individual models in my tx for every build. It’s easier for me to just set up individual models for each type of rx protocol. This means that I don’t want to make any quad specific changes on my tx side as that will end up making those changes across all models running that protocol.

With the way my brain works, it’s just easier for me to keep all quad specific changes on the quad itself.

I do have some global functions set up in my transmitter that I want to function the same across all quads- namely throttle limit on a rotary knob.

Fixed wing models are different- they all get their own model because they have unique trim settings.

Thanks Lemony - that makes sense.  I am used to flying models without a "brain" and have many models in my Spektrum radio...switching to a specific model for a specific airframe.  As these flight controllers store the info it kinda does make sense to have a "global" profile in the radio and the specifics programmed in the flight controller.  

That said - Im still old school and until my fleet grows to where its un-managable...im going to have a specific model for a specific quad...thats how my old brain has been conditioned.

There’s absolutely nothing wrong with having an individual model for each quad.

You should do whatever works best for you, there’s no right or wrong way.

I did it that way at first- but I experiment and swap parts around and change things so much that I started losing track of which model went to which quad.

I even tried taking pictures and doing things like one odd colored prop in motor position 4 or whatever, but, props don’t last forever and I like to experiment with props too.

I had a long gap where I didn’t fly rc things. Prior to picking it back up the last couple years, I was using old am or fm radios 2.5 decades ago. When I got back into it the whole concept of even being able to have individual models on my radio was new to me, so I was kinda able to start fresh and figure out what worked best for me.

Man, it was a steep learning curve.
Gotta say though, I love the whole digital radio thing. It’s a lot better than bringing a notebook with me that said things like: “1/4 scale cub, rudder 2 clicks right, ailerons 4 clicks left”.

Your quad fleet will grow soon enough. FPV is addictive.