Quick Workspace Toggle is a Blender add-on from young that combines workspace toggling with a pie menu and/or keyboard shortcuts. It builds on Blender's workspaces so you can switch between the ones you have set up using a single shortcut or a pie menu selection.
Setup is straightforward: install the zip file through Blender's preferences, configure a few workspaces that fit your needs, and assign shortcuts for the pie menu and/or hotkeys in the add-on tab. You can optionally define a main workspace. The add-on supports a maximum of 8 workspaces, ordered by numeric and alphabetic naming, so renaming a workspace with a leading number changes its position in the list and its spot in the pie menu, where slots 1 to 8 map to fixed directions.
Version 1.1 added a custom name filter that limits which workspaces appear in the pie menu, while button toggles are not affected by the filter. A demo video is available.