[2023] Error & Gray Screen

I recommend you start by checking your mods against the list of broken mods, both the first tab and especially the tab named Patch 1.17.0. Remove any broken mods you have and get the replacements where available.
https://pdxint.at/BrokenModCS

Are you able to start a new city fine or does that also result in a grey screen?

Please add the launch options -noWorkshop and -disableMods to Steam, and then try to start a new city again. This will tell us if mods are causing the issue or if it also happens without mods.

How To Set Launch Options

• Right-click on the game title under the Library in Steam and select Properties.
  
• Enter the launch options you wish to apply in the box (be sure to separate each code with a space). Should look like this:
  -noWorkshop -disableMods
• Close the game's Properties window and launch the game.

Your mod collection has two versions of Advanced Vehicle Options, which you're hopefully not subscribed to as that will break both of them. Always remove the old one when adding a new version of a mod.

Both Fine Road Anarchy and Fine Road Tool are broken and replaced by Network Anarchy.

Loading Order Mod is also broken and should not be used anymore, Skyve has replaced it.

And Extra Vehicle Effects is broken.