I use one of these power buttons for my PC. They plug into your motherboard and replace the switch on the case.

https://www.amazon.com/gp/product/B076CWLVS5

Everything is on one of these surge protectors that turns outlets on and off with the PC.

https://www.amazon.com/gp/product/B0084DFKPU

I just hit my power button and everything turns on. When I power off the PC everything turns off.

Not if your motherboard accepts individual connectors. Some of them have everything fused together in one connector instead of individual connectors for power, reset etc. You would need to look at the motherboard or look up a manual for it to determine that.

I use that button for my desktop which not very accessible under my desk. It is fine and good if you need HDD activity lights and a reset button. It is honestly a little fugly though. For my arcade I just use one of these surface mount buttons which would require drilling an additional hole.

https://www.amazon.com/gp/product/B076CWLVS5

Then I use something like this to turn on my monitor, lights and speakers when the PC turns on.

https://www.amazon.com/APC-P8GT-Power-Saving-SurgeArrest-Protection/dp/B002K8S2J6