If you use a print bureau and if you pick the sls (laser sintered nylon) option. Then the print is always supported at all times.
An sls printer produces a solid block of nylon powder with the actual parts within it, having been fused together by the laser.

It's one of the more expensive options, but it does mean you don't have to be too experienced when you design the part.

To design a part for fdm (fused depositon modelling) what most of us use - takes a bit more expertise and experience.

For example. I would print your buttons top side down, with the stalk either part of the button - or with a socket that a seperately printed stalk would fit into.

That way the flat part is on the flat bed and you can build up and out or in, for the stalks.