In the modern workplace the true gating resource is energy, not time.
Your teammates will run out of enthusiasm, willpower, and basic human energy far before the clock hits 5PM. This goes double for emotionally-draining tasks like email, chat, and administrative sundries.
Designate clear windows for the greatest energy vampires and do your best to ignore them outside of that period. Try an early morning, afternoon, and end of day cycle for messages. Block off other windows for actually doing deep work. Aim for at least a two-hour block in order to allow time to focus on a specific task or goal.
Push to remove the shallow work from your life. Audit your recurring meetings and kill the ones that aren’t needed. It’s amazing how much time we waste going from meeting to meeting that could’ve been easily handled or communicated through asynchronous means.
Look for opportunities to remove unnecessary weight from your schedule and your team’s schedule always.