Phaser 3 load many images

If you do have too many things to load, you could combine spritesheets into one, which then you would only be loading one spritesheet per object.
Heres an example:
image

If you really wanna get performant, you could have an atlas of everything which then you would only load 1 image ever. However that would require a lot more work to implement.

Also I would look at how big the images your trying to load are, because bigger image will be longer to load.