There’s a quote in Tamil, that loosely translates to “If it is worth doing, it is worth doing well”. The corollary to that is “Do only what is worth doing, and do that very well”.
No point doing many things at once under the guise of ‘productivity’. You are only fooling yourself, because the mind can only fully focus on one cognitively demanding task at a time. Either immerse yourself fully in the project or task, or decline / delegate. Your time is too valuable to be half-assing anything.
If you have a 1×1, be fully present. You will make the other party feel fantastic, and build a deep relationship that will drive far better outcomes.
If you are working on a document, shut all other tabs and focus on just the task at hand.
If you are attending a large team meeting, don’t check email or ping. Drive the meeting to the required outcome quickly by hyperfocusing on the issue at hand.
Make excellence a daily habit. And excellence will only happen with single-tasking.