Model: P03-600 Task: replacing a GTX 1650 with RX 580. Please help

PleaseHelpMe

I have a Predator Orion 3000 PO3-600 and I want to replace the GTX 1650 I have with an RX 580 Armor ITX. so basically I want to know if everything will work out in the end and this is my first time doing this sort of thing so if there is anything I should know please mention.
My Computer: https://www.harveynorman.com.au/predator-orion-3000-i7-9700-16gb-1tb-ssd-desktop.html
The RX 580: https://www.harveynorman.com.au/msi-amd-radeon-rx580-armor-itx-8gb-graphics-card.html
My three questions are:
1. Is it compatible with my computer?
2. will the RX 580 properly fit inside my computer? It's way bigger than the GPU I have. RX 580 is 0.79 foot on google search
3. The power Requirements for the RX 580 are: Typical Board Power (Desktop)185 W and PSU Recommendation are 500 W. I have 500w Power Supply, is that enough for everything? or do I need to get more watts?

i really need to get this right the first time because I don't have enough money to try again. thanks for helping