I’m on patch 1.15.10.0 and I’ve now got the same problem: super slow loading up to abt. 80%, where it stops completely. Removed all addons from the Community folder - same thing.
Visually the super slow loading is different to earlier in that the loading screen turns black. The Paris loading image disappears soon after start, and only the loading bar at the screen bottom is shown, stopping at abt. 80%.
Seems the only solution is a fresh install of MSFS, again (not the 1st time!). Last time the download + reinstall took some 8-9 hrs, plus extra time for the various updates…
So WalNowhereman, you’re not alone. A Spanish saying comes to mind: Mal de muchos consuel de tontos - Misery of many is consolation for fools.