There’s a solution! But its not the prettiest.
What you can do is set it with two decimals, then use a formula to round, the only down side is that this formula is then read only, so if you want to edit there will be extra clicks or the info showing twice. Here’s the set up:
If(
Float >= 1000000,
ToText(Round(Float / 1000000, 1)) + “m”,
If(Float >= 1000, ToText(Round(Float / 1000, 1)) + “k”, ToText(Float))
) + “$”
The weird thing is that I think the Round function actually can’t round to zero decimals… Round() function creating decimals even if places = 0 Not sure if this will be solved any time soon.
What i recommend in order to not have the same field twice with two visualisations, is to hide the raw number and add a button for “Edit price” which will then ask user for the number, and then edit it. It’s a bit less pretty than other solutions, but more custom as you can set the formula to be whatever you want. (Except for a number with no decimals apparently? 
There might be a solution im not aware to this on though) Lmk if you need more guidance on the button set up.
I just tested it, indeed the different types of floats can be set to different decimals without it affecting the actual data. The number of decimals in a float is indeed just visualisations, except for 0. So the dropdown contradicts itself in functionality without being clear to the user (which is where your mistake happened). I honestly would go for two different field types. “Float” and “Integer”. And floats can be set to have 0 decimals (while still being a float). This would help with being able to edit fields after creation. (Because under the hood its two field types baked into one).