With the keybind set to its default, the mod functions as intended. When the keybind is changed, the mod is borderline unusable. While the scroll-to-zoom and no-crosshair features still work as normal, pressing the changed keybind causes the screen to zoom in and out a few times and not display the spyglass overlay. Also, if the spyglass is in your inventory and not your hotbar, it will not even attempt to move the spyglass to your offhand as normal. The zoom keybind only functions normally if you already have the spyglass in your hand or if you are in Creative mode and don't have a spyglass in your inventory at all.
If needed, I can record and post a video showing more details.
Also, a quick feature request: When using the hotkey to pull the spyglass from your inventory into your offhand, swap the items back after releasing the hotkey. If that isn't possible, it would at least be helpful to have a config option making it so you can only use the hotkey to access your spyglass if it is in your hotbar so that you don't have to rearrange your items when you're done with the spyglass.