The steps to synthesize perfect gems in Big Pineapple 2 are as follows:

1. Enter the game, click on the red space on the right, and then the options will pop up.

2. Then click Enhance in the pop-up options.

3. After opening the enhancement interface, we click on the Perfect Gem option.

4. Then click on the perfect gem that needs to be synthesized and upgraded.

5. Then click Synthesis on the pop-up interface.