Is it better to run later Resource missions (such as AB-3) when I need a lot of blue overclock material?

You should always run the highest tier you can.

You can trade 1 purple for 2 blue mats in the shop if needed.

There's in-game event every month with 100% uptime. Farm the resources and exchange them for overclock bundles. It's more efficient and reliable than AB-5, let alone AB-3. (You can buy Blue mats or Purple mats from event shop seperately whereas you get mixed rewards from resources runs)