Sounds like a bad control panel. Very common problem on these. If service mode runs through OK when you do the heat dry/normal/heat dry/normal sequence but you cannot start a regular cycle then the membrane circuit for the start key is bad. Replace the "console assembly". That's what they sometimes call the control panel. Be sure and order the right color.

Check the keypad with a meter, see the tech sheet.

Check the motor windings with a meter.

Check the motor's start capacitor.

Check the door switch. The one that is connected to the motor and heater.

Here are your parts
Parts for Maytag MDB7609AWW2 Dishwasher - AppliancePartsPros.com

The tech sheet is too big to attach in this site so I had to use a third party site.
Unclick the Use Our Download Manager and then download it using the grey button. Otherwise the site may put software on your computer that you do not want.
Download MDB7609.pdf

Does sound like a control board problem since ypou say all keys/lights are flashing at the same time.but I would try a couple things before replacing it.

Remove power from the unit for several minutes to see if it will reset.

You could check the keypad with a meter, see the tech sheet.

Perhaps try the following.
Connector Cleaning / Checking
Unplug the unit
Open it up
Remove the ribbon cable from the keypad to the control board at the control board.
Clean the edge connector. Use electronics contact cleaner or isopropyl alcohol.
If it is the type where there is not a connector just the insulation is removed, it can be cleaned with a pencil eraser. Do not use an ink eraser as it is too abrasive.
Check the tracks in the ribbon cable for hairline cracks. A magnifying glass helps here.
Would not hurt to clean the connector on the board. Use electronics contact cleaner or isopropyl alcohol and a tooth brush. Be gentle and do not reconnect till all the solvent evaporates.
Reconnect everything and give it a try.