Greetings

I admit, I also was attempting to solve this issue at the same time. I've been able to succeed. However - I can share with you some information that might assist you.

    I apologize in advance if it won't be structured well/provides in-depth information.

• Screen Resolution: This is one of the main ways to fix the 'lag' of the game. Less things to render with heavy graphics = faster, with the issue of everything looking blurry, pixelated & hard to read. The best way to fix it would be thus to increase things like:

•     Anti-aliasing
•     Sharpness

The first would make it so that edges are less block, while sharpness makes the image "sharper" by essentially bolding everything. 

(In regards to Anti-aliasing, I know there's some separate settings that are experimental/difficult to comprehend. From what I've gathered you can tweak how the aliasing looks like overall. Not sure but see if something in there may look different.)

• Cockroaches Amount
  Believe me when I say that this is so much of a common issue that's included in the 'Tips & Tricks' section. The game has to render every cockroach that way on food that's kept on the outside & not stored properly. Meaning it not only keeps in check if food will spoil, but then to where to add them & consume the food. So removing them (setting them to 1 is the lowest limit) Actually is recommended.
• Shadows
  If you're going to reduce light, shadows are the next biggest issue.

Right now I don't think I have any on the mind advices.. But thankfully every feature now explains what and how much, resources it takes off your operating system. Letting you better understand what options you can remove to obtain a better impact in performance.

  That being said, no matter what: lights overall, will consume a heavy dose of performance. It's something one must endure eitherway - but I'm not entirely certain if you can bypass it by utilizing alternative light-sources.

If all else fails - one could simply increase the 'gamma' & voila that you can see a bit better.

Let me know if there's more you need help with!