Can I limit my dock to only show up on the main display?

Solution 1:

Your only options are both workarounds:

  1. Uncheck "Displays have separate Spaces" under System Preferences > Mission Control
  2. Pin dock to right or left instead of bottom (obviously not ideal if you're a bottom pinner)

More details here: https://www.makeuseof.com/tag/how-to-keep-the-mac-dock-on-one-screen-in-a-dual-monitor-setup/