To be fair, developmental disabilities (which this sounds like) don't usually present right away. Your kiddo probably was still meeting milestones until he wasn't.

This definitely sounds like something serious. I don't have any official credentials, but I worked with kiddos with ASD for several years and also have ADHD myself.

One big thing I noticed with this comment is your focus on him not knowing something is wrong. Does it really matter? I know it sucks to clean up juice and it's a waste, drawing on the walls is another cleaning issue, and spraying air freshener on the tv isn't great ... But it won't end the world here. Obviously it's desirable to not have it happen, however for whatever reason these things are satisfying to him.

However there are ways to manage it. Scolding is clearly not working. Pm me if you want my reasoning behind this.

Try to avoid negative phrasing. Saying "no drawing on the walls" leaves way too many other options (everything else).

The better course of action here is telling him what you want, and focus on where the behaviour is good. Instead of immediately taking away the pens and scolding, you can redirect him to a piece of paper, and maybe replace the type of pen he took with a kid friendly one. Verbalize it too, "we don't draw on the walls, we draw on paper!" with a pleasant tone will get the point across without starting a meltdown. Also, "mommy's pens are for mommy to use, here are your pens for you to use!" If he likes the vertical wall, get a roll of paper and tape some to the wall for him to draw on. Create situation where his actions aren't bad, so you can praise him for drawing on paper and the things you want: "I love to see you drawing on paper! And with your pens too?! I love it!" This will take a while to work, but with time and consistency it can help. Also it avoids the negative connotations of getting in trouble, which will probably not work well here.

There will always be reasons for time outs and other generalized punishments. Try to avoid them if it's possible and redirect instead.

With the method above it also becomes a choice when he starts to know what you expect. Ex: You can draw on paper or I take away the pens, you can run outside or stay inside and use your walking feet, etc. Try to use natural consequences, if he doesn't want to draw on paper then you take away the pens after he makes his choice. It gives him a second chance to remember the rules before getting in trouble. Also with consequences, always use the format "you did this, so this happened" (you drew on the walls, so I took away the pens. We draw on paper, not walls". It's really redundant, but it helps young kids even without a delay. Heck it helps me talk to myself and I'm an adult. Say it factually and as many times as needed.

Using "we don't [do this], we [do that]" statements will relieve the pressure on him too. It's less personal and I also like it because it reminds me to say something truthful. I can't say anything I wouldn't say about myself.