“Can psychosis be treaded with therapy?”

Not by itself most of the time, unless it is part of a reaction to trauma.

Self-treatment: Self-care steps that may be helpful in some less- serious cases:
Get support from family and immediate friends
Communicate and expression of your thoughts and feelings
Cultivate and develop social skills
Avoid drug abuse
See a doctor if you notice:
Memory loss, slowness in activity and thought, disorientation, speech difficulties
A child is presenting with symptoms of delusion
See a doctor immediately if you notice:
Fear, mistrust, hostility, hallucinations, anger
That the patient is a threat to themselves or to those surrounding them.

See this link...
https://www.nhs.uk/mental-health/conditions/psychosis/treatment/