[2022] Game crashes in loading screen or gets stuck shortly after loading-in

We'll need to see the output_log.txt (called player.log on Mac and Linux) to see what's causing it. Here's where to find the log depending on your operating system. To easily find the local files for the game, right click your game in the Steam library, select Properties, go to the Local Files tab and select Browse local files.

Windows
\SteamApps\common\Cities_Skylines\Cities_Data\output_log.txt

Mac OS X
Users//Library/Logs/Unity/Player.log

Linux
~/.config/unity3d/Colossal Order/Cities: Skylines/Player.log

As we can't attach files here on Steam, you will need to upload the file somewhere else. Here's a few sites you can upload it to, which do not require you to sign up first:

https://uploadfiles.io/ - free, no sign-up, can handle large log files
https://paste.ee/ - fast, no sign-up required (some log files will be too large for it though)
https://zerobin.net/ - bit clunky, but can handle huge files, no sign-up required

You have both Metro Replacer and Metro Overhaul Mod. Those two shouldn't be used together. If you have used MOM in your city, keep that and remove Metro Replacer.

You also don't actually need Plop The Growables when you have Ploppable RICO Revisited. Just make sure to go into Options for Ploppable RICO Revisited and enable the options for growables too.

Advanced Toolbar is really old, so I recommend you switch to More Advanced Toolbar or Resize It

The issue seems to be related to some UI, so let's try having Steam verify the game files and see if that does the trick. Here's how that's done:
https://support.steampowered.com/kb_article.php?ref=2037-QEUH-3335

It's most likely a mod or two mods being incompatible that's causing it. Not sure which ones though. Best way to confirm that it's mod related is to try and start the game with the launch options -noWorkshop and -disableMods in place in Steam. Then start a new map and see how that goes. If everything is fine, then it's a mod problem.

How To Set Launch Options

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

Actually that sounds like maybe you're running out of memory. If you haven't already, I would recommend you define a custom size pagefile of 32 GB. It's faster to do than go through all your assets, so worth a try.

https://steamcommunity.com/sharedfiles/filedetails/?id=2114415052&searchtext=pagefile

If you have a link to the asset in question, others can test it and see if they also have problems. The creator would surely like to know if it's causing problems like that.