Difference between HMO and POS plans?

Difference between HMO and POS plans ??
I know everyone hates this but gotta get it straight once and for all

HMOs hire a their own doctors/providers . . so if u buy this HMO plan u will only get discount if u see the HMO enlisted doctor.
only limited services will be covered by the HMO plan for eg . . they will cover issues related to heart but not eg ur teeth or ur skin.

if u want a specialized doctor to look after u for eg orthopedic surgeon . then HMO will only pay for u If ur primary HMO enlisted doctor referrs u

in POS . . . there are POS enlisted doctors . . but u can still see a doctor who is outside the POS network and POS will cover the cost for that but POS will provide less discount if u see doctors out of the network vs if u see the doctors that they have chosen .

this is the basic difference that i was able to decipher cuz it is given in the most shittiest way possible in FA