06 Pontiac Grand Prix. new thermostat, water pump, ICM, and serpentine replaced. Car is now taking multiple tries to start , any suggestions?

Bad ground to motor. We added a second #6 cable from battery neg to block on the '99 Sunfire, starts a Lot faster!

Were the spark plugs and plug wires replaced at 90,000 miles?

Have you had a mechanic check out the engine data with their scan tool to see if all the senors are working with in spec?

The things you've had done shouldn't effect the motor starting.

The battery is always the first place to start. Then the Starter.

One commonly overlooked part is spark plug wires. I had a Fiero many years ago that would not start in the rain. The water in the air penetrated the rubber. I changed them out and never had the issue again.

Get the battery charged and load tested.  Replace crank sensor.  Replace fuel pump relay.  No luck, when it does not start, spray starting fluid on intake or in a vacuum line.  Try to start.  Car starts, check fuel pressure while cranking.  Car does not start, check for spark.