Finally, a question where i can shine. You don't have to do anything specific. Just do things.

Use a headset with your phone or laptop: You are on a call. Most people don't speak much at online meetings.

Take a little nap? Thinking.

Want some time alone? Go to a meeting room. Works even better if the room has glass walls since you can see them and they can see that you are "busy", but no one sees your screen.

Have multiple monitors. There's always something work-related on at least one screen.

Have fields of interest that blend in. If one of your hobbies is vaguely related to work you are golden. You can totally read something unrelated to work during working time if it seems most your attention goes towards work. (See multiple screens and some switching back and force.)

Shift your working hours slightly from the norm, i.e. come 5 min earlier than others.

Don't hide windows with non-work stuff when someone sees them. Too late. Act as if you have nothing to hide.

Do a reasonable work-life blend. Work overtime occasionally at odd hours and make managers know that you solved an emergency in your free time. Gives you an excuse to leave early or slack off the next day and any other day.

React to emails with a resonable delay. Of course, you can help, but not right now. You are busy.

Block your calendar and decline invites.