When you start your dishwasher and after it starts it’s wash cycle, open the dishwasher, it will stop. Look inside to check the water level, it should be at least one inch or better.
All dishwashers have a fill solenoid value. If the water level is low you will not get a proper cleaning cycle.
The solenoid can get hard water buildup and restrict water volumes/flow going into the washer.
(The solenoid is on a fill timer, which accounts for the low water level if dirty.)
I replaced one on a 25 year old machine and afterwards it cleaned better than newer dishwashers.
It’s a fairly common part at most appliance parts stores for around $10 bucks.