The sleep could be what’s holding you back. Most people get stronger early in their lifting, like the first year regardless of their nutrition and recovery, as long as they show up and lift. As you get stronger, the newbie gains level off, especially considering you’re probably lifting heavier weights. Keep that in mind. The more you lift (in months/years), the gains will level off.
Those calories seem pretty low as well. Are you losing weight? It is very difficult for an experienced lifter to add strength while losing weight. I don’t know your body weight. 1500-1800 calories may be okay. My wife is 135 pounds and she is around there. I’m 195-205 and need about 2300 maintenance calories. That shoots up to 3000 or so when I add in activity. Find a BMR calculator and check for your weight, and also track your bodyweight to see how to fluctuates relative to your strength.
Finally the rest thing. I also meant how much time between workouts. Generally resting until you’re ready for the next set during workouts is fine. I rest anywhere between a minute (for light things like pull-ups) to 3 minutes for bigger lifts. Sometimes, if I’m pushing for a cycle PR, I might wait 5 minutes. As long as you’re ready to give a good effort on the next set, it doesn’t really matter.
What IS important is to get enough recovery between workouts. How often do you lift and what muscle groups? Your body generally needs 48 hours in between workouts (for a muscle group). Any more frequent and you need to dial the intensity down.
One last thing, do you ever just take a week off? Your muscles won’t fall off. I lift pretty intensely, and take off a week every two months at the most.