Agree with locking down sites/apps - if you find your hands just start auto typing addresses in the toolbar as a coping mechanism for dopamine hits then lock up the problem sites and throw away the key. Set the redirect to something to try to queue you/remind you why you have it blocked (e.g a webpage with a quote). Leechblock is a good in browser alternative if you are on a work pc without access to pihole (e.g. through vpn etc) - you can set password and throw it away.

I would also add to all of this if you have the ability to work in person with your screen visible it may help you to keep on track if you feel pressure of being "caught" slacking. Research "body doubling" multiple approaches to this.

Above might seem extreme but some tricks like this can help you use your other psychological traits as a stick against your adhd trait (because we all know the carrot only lasts temporarily).