I deleted my game folder and reinstalled Stardew valley but every time I try to open the map in the Modding API the game crashes.
This is the error that pops up:
[06:20:16.687 PM] An exception occured in XNA UpdateTick: System.MissingFieldException: Field not found: 'StardewValley.Game1.content'.
at NPCMapLocations.MapPageTooltips..ctor(String names, Int32 nameTooltipMode)
at NPCMapLocations.MapModMain.GameEvents_UpdateTick(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at StardewModdingAPI.Events.GameEvents.InvokeUpdateTick() in Z:\Projects\SMAPI\src\StardewModdingAPI\Events\Game.cs:line 80
[06:20:16.699 PM] [ERROR] An error occured in the overridden draw loop: System.NullReferenceException: Object reference not set to an instance of an object.
at NPCMapLocations.MapModMain.drawMarkers(GameMenu menu)
at NPCMapLocations.MapModMain.GraphicsEvents_OnPostRenderEvent(Object sender, EventArgs e)
at System.EventHandler.Invoke(Object sender, EventArgs e)
at StardewModdingAPI.Events.GraphicsEvents.InvokeOnPostRenderGuiEvent(Object sender, EventArgs e) in Z:\Projects\SMAPI\src\StardewMod
D:\SteamLibrary\steamapps\common\Stardew Valley>

I'm not sure if there's something effecting it on my end or how to fix it

I thought that might have been it as well Clxs so I completely uninstalled all mods, deleted the Stardew folder, removed everything from the NPC Map Locations mod and did a clean install of Stardew, and still experienced this problem.

Mmm weird. Do you still get the same error output as the above after you've deleted your mods folder?

It hasn't updated yet, the latest version of Stardew Valley is 1.11, SMAPI only supports (at the moment) ver. 1.1
So unless you can roll-back or have a GOG copy at ver.1.1, you'll have to wait unfortunately.

This is likely a problem with NPCMapLocations, not SMAPI. SMAPI is compatible with 1.11, but some mods wont be.

I wanted to let you know I am currently using SMAPI 0.40.1.1-3 and I am not having any issues with NPC Map locations.

You definitely have an outdated copy of NPC Locations hidden somewhere then.
Check both the mod folder that next to your game exe and the one in %Appdata%/Stardew Valley

Yup, same error

Make sure you're running the latest version of the NPC Map Locations mod, which has been updated for 1.1+. If you have any trouble, feel free to contact the author from the mod page.