Q.rhododendrons
can rhododendrons be trained to grow upward by staking them and tying them. i have some that just want to sprawl along the ground and have little height to them.
It is difficult to compete with a plants natural growth habit.
Pruning may help you with shape.
Here are some links with more information.
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/pruning-rhododendrons.htm
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/rhododendron-care.htm
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/issues-with-rhododendrons.htm