There are many species & varieties of Hoyas sold on the market. You can find at least 1 that catches your fancy because the foliage comes in a variety of shapes, sizes, colors & textures.
Mine grows at a moderate to slow rate indoors. The lower the light, the slower the growth rate. What I’ve found is that different Hoyas grow at slightly different rates.
Hoyas need bright, natural light to do their best. They need as much bright light as possible to bloom indoors. That’s where a west exposure comes into play.
If you think yours lacks humidity, then fill the saucer with pebbles & water. Put the plant on the pebbles but make sure the drain holes &/or the bottom of the pot aren’t submerged in any water.
You can prune a Hoya to control the size. Don’t prune off too many of the short stalks from which the flowers emerge because that’s where they bloom off of next season.