What Android phone do you have? I've just tested on an S21 and the camera app loaded in less than 1 second. Felt more like 0.25 or 0.5 seconds at worst.
Don't forget to count time activating the phone itself. Admittedly I have a cruddy phone (Moto G4), but the phone app itself takes about 1.5 seconds to start, on top of 0.5-several seconds to come out of sleep mode (sometimes it takes 5-10 seconds). And if the lock screen is up, opening the camera takes longer due to the weird swiping motion needed which always takes me a few tries.
Contrast with my DSLR, the on switch is colocated with the shutter. I can turn it on and get a photo in 1.5 seconds.
I just leave my D5600 on all the time and let it go into standby. It can sit for months like that and still take hundreds of photos. It wakes up and focuses with a single half press.
