In July you are not going to beat the crowds at all, its high season.
Here is something to consider. Take the early morning KTEL bus from Chania to Sougia. AS I recall it departs around 5am. Sougia is a small village on the Libyan Sea. The bus trip is breathtaking as the route is winding as you cross over the White mountains.
This is actually one of the buses that go to the start of the Samaria Gorge. Stay on the bus and finish the route to Sougia. You will have some time to wander the village and perhaps take a dip in the sea. There are sea caves way over to the left from the village.
At 8 o'clock a ferry will arrive which will take you along tone of the most rugged shorelines you will ever see. You will arrive at Agia Roumeli around 9am. This is where the Sameria Gorge hike terminates. You can take a shuttle to the bottom entrance of the Gorge where you can explore at your leisure without having to do the steep top of the gorge hike. You can get to the iron gates and probably all the way to the last rest stop at Christos before you meet the fast hikers from the top.
Head back to Agia Roumeli and have a couple of hours on the beach there.
Take the ferry back to Sougia and the KTEL bus will be waiting for you to take you back to Chania.
I suggest this because many people report they are totally exhausted after the downward hike (its 16km) and pretty much have to spend most of the next day resting sore muscles.
You can also take the excursion that starts at Kissamos harbour. There is a excursion boat that takes you to Gramvossa which has a good beach, a shipwreck and a 14 th century Fortress to explore. The boat then takes you to Balos lagoon. It is a large shallow lagoon with lots of beach areas which means you can get away from the crowds. Having said that, this is a popular excursion so the boat likely will be pretty full. There will be crowds there. The excursion is worth it.
Chania old town will take you a full day to really explore the maze of back alleys and the Venetian harbour. If you choose to do what I have suggested you will not even need a car.
This can be done by bus excursion or the KTEL bus system.
Here is what you will see.
Chania 2022. https://www.flickr.com/photos/stanbr54/albums/72177720299646015
Chania Sougia and Plakias 2019
https://www.flickr.com/photos/stanbr54/albums/72157711266062752
There are some videos of the bus ride. Watch out for goats.
Ferry trip Libyan Sea https://www.flickr.com/photos/stanbr54/albums/72157653434073393
Samaria Gorge from the bottom https://www.flickr.com/photos/stanbr54/albums/72157670610409530
Crete Libyan Sea villages https://www.flickr.com/photos/stanbr54/albums/72157645487373222