To make sure your packages are properly installed use this:
Framework Installer Tool from MTS2.
I had confused this with the
helper monkey (which hasn't been updated for any EPs). This is
not that.
This a framework installer updated to Ambitions. To make this clear: It
does not install CC for you but it makes sure all the necessary folders needed to use CC/mods are installed i.e. set up properly. It is simple and easy to use and answers to what folders, cfg, or .dll files are missing or not placed properly are quite easy to understand.
I had been unable to get my (base-Ambitions) games to run properly and this pointed out the error (missing file).
If you still have issues after that it may be cache files or file bloat as you suspected. You could check MATY for threads related to your issue. I had an identical problem ages ago but can not remember exactly what thread gave me the answer. Also awesomemod resolved most of the game lag.
Be sure to do a solid thread search over there before asking for help. It will take some legwork but I'm sure you'll find the solution to your issue somewhere in there. Just a suggestion.