There seems to be two problems that need to be dealt with.
The first is the food particles left of glasses and cups and the second is the residue that is hard to get off even with scrubbing.
The food particles are usually caused by poor circulation or not enough water. The first image below shows how to access the sump and check the filters and screens. You'll notice a "check valve" rubber flapper that is suppose to prevent dirty drain water from draining back into the tub.
Run a normal wash cycle and check for the following doing the cycle. Check water level at the beginning and at various places during the cycle. Check the water level in the rinse cycle especially. Sometimes the water will drain out during wash leaving food behind.
The residue problem is more difficult to deal with because normally that would be a hard water problem but you say the problem just started after 14 months.
There are two kinds of film left on glassed: Soap and Mineral film. Soap will usually rinse off with a little effort. Mineral film is more difficult to rinse off. From the description you have this is the problem you have. You can scrub this film but when the glass dries the film is there.
The dishwasher cleaner did not work but there is one trick you can try.
Load the dishwasher with clean glasses that have the film that can be seen. Select and run a rinse only cycle. Once it fills pause the unit and add 2 cups of White Vinegar to the water. Let the rinse cycle run through and the check the glasses.
If they are clean then you do have a mineral hard water problem.
This may take a question or two to resolve so give me a reply with what you find for further assistance.