I'm not with Laminar Research, just a fellow simmer in the UK.
I have looked through your Log.txt file and have noted that you have a great number of zortho4XP tiles (line 335 - 1430), which is fine in itself, but these all need to be at the bottom of your scenery_packs.ini file and below any airport scenery files.
Currently, you have the following airport scenery files 'below' all of your zortho4XP files:-
1431 Custom Scenery/Aerosoft - KPUW Airport Pullman-Moscow Mesh/ - MESH file, may need to stay below zortho4XP files?
1432 Custom Scenery/CA-CYYZ-C-Toronto Mesh/ - MESH file, may need to stay below zortho4XP files?
1433 Custom Scenery/Nimbus Simulation -Z- KATL V2 - Atlanta/
1434 Custom Scenery/Z KDEN Mesh/ - MESH file, may need to stay below zortho4XP files?
1435 Custom Scenery/Birmingham_autogen/
1436 Custom Scenery/DallasXP_Buildings/
1437 Custom Scenery/DallasXP_Exclude/
1438 Custom Scenery/DallasXP_Forests/
1439 Custom Scenery/Los_AngelesXP_Buildings/
1440 Custom Scenery/Los_AngelesXP_Trees/
1441 Custom Scenery/San_Francisco_XP_Buildings/
1442 Custom Scenery/San_Francisco_XP_Mesh/ - MESH file, may need to stay below zortho4XP files?
1443 Custom Scenery/TampaXP_Buildings/
1444 Custom Scenery/zz_Denver_XP_Mesh/ - MESH file, may need to stay below zortho4XP files?
1445 Custom Scenery/ZZZ DD Seattle Airports XP Terrain/
1446 Custom Scenery/ZZZ DD Washington XP Terrain/
1447 Custom Scenery/CFXP - Static Aircraft Library/
The scenery_packs.ini file is text editable and can be opened in Notepad by double clicking on it. The file itself can be found in the C:\X-Plane 11\Custom Scenery folder.
I would suggest that you save a copy of your original scenery_packs.ini file first, before any editing of the original takes place!
Basically, what you need to do is cut all of the above-mentioned airport scenery files (NOT MESH FILES) and paste them above all of your zortho4XP files. Following that, close up any gaps where the airport scenery files originally came from.
Also, I note that line 1130 Custom Scenery shows a 'mesh' file i.e. ZZZ_Skyline Simulations_KCVG_Mesh/ located right in the middle of all your zortho4XP file. This mesh file should be after all of the zortho4XP files
Lastly on line 334 Custom Scenery you have an overlay yOrtho4XP_Overlays/ file, which I understand should be placed above the Custom Scenery/Global Airports/ file.
In essence, all scenery files in the scenery_packs.ini file should be ordered as follows: -
2. Regional Sceneries
3. OSM Data (for example World2XPlane)
4. Libraries (but Libraries can be positioned anywhere in the ini file)
5. Global Airports
7. Mesh Data (... HD Scenery Mesh v3 ... from alpilotx)...
Once you have made the required changes, save the file immediately and reload XP11 to see if it makes any difference?
If push comes to shove, copy and paste all of your custom scenery files to a temporary safe place out of the XP11 file structure, to see if the XP11 applications starts up OK? If it does, start reinstalling the custom scenery files a few at a time, but always make sure that your scenery-packs.ini file shows the files in the correct order after starting and closing XP11 each time.
More information on scenery-pack file ordering on YouTube!
Hope this makes sense, but let me know if not?