I have a few tricks. I have a work laptop and a gaming computer, and I do all my personal work on the gaming computer. That helps separate the two. I have a workspace which gets me out of the house and keeps me focused while at work, so I can get it done quicker and ultimately spend less time on the computer. I also have a few outdoors hobbies, and a few indoors hobbies that are away from the computer. But of course I can't make progress on my computer projects off the computer, so that's still a conundrum I can't solve.
I am at the point where I wonder if maybe I should work outdoors or offline, in order to regain my online time. But I'm not sure where to take that.