Can you experiment with using nonverbal communication to signal that you’re ready to go? Things like:

• If standing, shift your feet so they’re pointing away from the person (if ineffective, can escalate by rotating the whole leg away, which you can then escalate by shifting more weight to the turned-away leg)
• If sitting, put your hands to your knees/lower thighs (think an extremely subtle version of the Midwest USA joke where you slap your knees and say “welp!”)
• If sitting at your desk, gradually begin rotating back to your work (gently swivel seat back so your legs are under the table, can escalate by rotating your torso back to your work while keeping only your head turned, and if they’re still super clueless you can return your hands to your keyboard/work as well)