Hi AS,
You can turn on DRS and it will take care of the movement if the load is not balanced (If set for fully automated).
You should understand here how HA works. You have two hosts which are in a HA cluster. When one of the hosts went down the machines moved on to the second host. HA will not move the machines back to the first host if its powered back on. because the machines on second host will move to first host through HA only if the second host went down.
This is a job for DRS. If the DRS is on check the automation level and see if its fully automated. It will move the machines. When the load is balanced you could use the level that's preferred by you.
Abhilash B
LinkedIn : https://www.linkedin.com/in/abhilashhb/