>>121744880just practice them for 10-20 minutes then do whatever else you want for the rest of your practice.
chord changes are the hard part. When I was starting out I would find what chord changes I sucked at then just do them over and over for five minutes then move onto something else.
If you do it every day then you'll build them into muscle memory.
Also you don't need to learn all the scales. Learn a few basic scales and all their positions then you can basically just add/remove notes from them based on your ear and that's basically covering dozens of scales. Most scales are derivative of the basic scales.