[PerkyAcups]

I found that bras like these are very stealth: https://www.amazon.com/BESTENA-Seamless-Comfortable-Everyday-Removable/dp/B07DGPZM9S/
On Ebay you can find some that are made of an even thinner fabric. Their wide straps made of thin fabric makes them super stealth.

You can also find camisoles with hidden bras (slightly padded). https://www.amazon.com/Knuffnee-Women-Shelf-Cotton-Undershirts/dp/B0BXP7975L
These too are practically undetectable from the back, but the padding will indeed add some shape to the front. Under a coat or a hoodie nobody would clock them.

 I just gave you two random examples. May brands make clothes like these.

That first bra attachment is very similar to what I have now I wore all day today under a tight tshirt. I wasn’t concerned once someone might notice. The thin wide straps are invisible. I will get more like these. 
i think I want to order camisoles.