If you don't know what is occlusion CTD,never mind.
But Captial Whiterun Expansion always has this bug whether you use other mods or not and you can try openning map in Whiterun using Captial Whiterun.CTDs...
Also,JK+DOS Patches from JK's Skyrim_Dawn of Skyrim_Capital Whiterun - Fixes and Patches at Skyrim Special Edition Nexus - Mods and Community (nexusmods.com) and Skyrim Special Edition Nexus 的 Whiterun 扩展城市补丁 - 模组和社区 (nexusmods.com) have similar occlusion CTDs,reported by More Capital Whiterun Expansion patches at Skyrim Special Edition Nexus - Mods and Community (nexusmods.com) saying：
        The JK's Skyrim + Dawn of Skyrim patches require somohexual's fixed patch (see mod requirements), which while being mostly well-made, requires some extra installation steps for a smooth gaming experience. FAILING TO FOLLOW THESE INSTRUCTIONS ARE LIKELY TO CAUSE CTDS, SO PLEASE READ CAREFULLY! I will close any bug reports from people experiencing CTDs who have not followed these instructions:

• Make sure to follow Somohexual's instructions at their mod page. In particular, use SSEEdit's autoclean utility to clean Fredtheviking's patches.
• While probably with good intensions, Somohexual made the mistake of stacking several occlusion planes in every building. This is known to cause CTDs, and since they are anyway not likely to improve performance, they need to be cleaned out using SSEEdit:
  

a. Open JK-DoS-Whiterun Expansion Patch - Fixes.esp in SSEEdit.
b. Go through all Worldspace records, select all PlaneMarker objects with a white background (i.e. the ones added by the mod), and press Delete.
c. Save the file.
This mod is aimed at fixing all these CTDs with EFPS support,making your Whiterun Map normal again.
   If you use JKs Drunken Huntsman or JK Bannered Mare or Whiterun Metropolis or Whiterun has walls(high walls) and their patches,make sure to delete all plane marker records in Whiterun World in the way just like Jonado1 said.
  I also provide patches for Capital Whiterun Garden and This is Jorrvaskr.Hope you enjoy my patches.
  Suggested Load order:
  Occ_Skyrim_Tamriel.esp;
  JKs Skyrim.esp;
  Dawn of Skyrim.esp;
  SurWR.esp;
  This is Jorrvarskr.esp(Optional);
  Occ_Skyrim_JK_Skyrim_patch.esp;
  Occ_Skyrim_Capitol_Whiterun_patch.esp;
  Occ_Skyrim_C-Whiterun_JK_patch.esp
  Myq High Garden.esp(Optional);
  JKs Skyrim_Dawn of Skyrim_Patch.esp;
  JK Whiterun Expansion Patch.esp;
  Whiterun Expansion Dawn of Skyrim Patch.esp;
  JK-DoS-Whiterun Expansion Patch - Fixes.esp;
  JK-DOS-CWre - This is Jorrvaskr Patch.esp;(Use when using TiJ)
  JK-DOS-CWE Occlusion Fixed.esp
  JK-DOS-CWE Occlusion Fixed - This is Jorrvaskr Patch.esp(Optional);
  Occ_Skyrim_Capital_Whiterun_Garden_patch_fixed.esp(Optional).
  
  Notes：1.Don't use Normal Occ Patch for Capital Whiterun Garden.
 2.This mod is provided for ESL version for JK Whiterun Expansion Patch.esp;
  Whiterun Expansion Dawn of Skyrim Patch.esp;
  JK-DoS-Whiterun Expansion Patch - Fixes.esp; so you actually don't need the origin ones.I will provide some patch replacers for those esl main files.