How to Stop the Day Counter from Covering Other On-Screen Info
Identify the Conflict
The day title appears as an overlay near the top of the screen, in the same area vanilla uses for title and subtitle text. If you use other mods that show HUD elements or titles there, the day counter can overlap them, making both hard to read.
Reduce the Overlap
First, check whether the mod has a config option for the overlay's screen position or vertical offset. If it does, move the counter slightly so it no longer sits on top of your other HUD. Save the config and restart.
Adjust GUI Scale
If there is no position setting, changing your GUI scale in the video settings can help. A smaller GUI scale shrinks all HUD text, so the day title takes up less room and is less likely to collide with other elements. Test a couple of scale values and pick the one where your HUD stays readable.
Time Your Other Overlays
Because the day title only appears briefly at the start of each day, you can also avoid the clash by not triggering other title-based mods at dawn. Sleep to advance the day, let the counter finish, then activate whatever else you use.
Last Resort
If the overlap is unavoidable, disable the day counter in its config and rely on the F3 debug screen for the day number instead.