Similar situation here.
I’ve emailed and spoken with immediate team members, and emailed a couple of partnership groups I work with to say thanks for your support over the years etc. Also going to speak to a few contractors who have worked regularly for me.
Why wouldn’t you want to let people you know and have enjoyed working with know that you’re going? Isn’t it just polite? Also, I’ve no need to be burning bridges.
I’m under no illusion that life will just go on and once my successor is in post no one will give me a second thought, but for me that’s no reason to just vanish without a good bye.