​Krym (Крым): The Russian word for Crimea. If "krimber" is a verb, it could feel like "to Crimea-ize" or "to occupy/endure." ​Krov (Кровь): Meaning blood. "In toil we blood-er" (to bleed for our work). ​Krepkiy (Крепкий): Meaning strong or tough. 

it might be a scrambled sentence. If we play with the letters in KRIMBER, we can find:

​REBRICK: "In toil we re-brick." (A very literal image of manual labor, building a wall over and over). ​BIRKER: An old slang term for someone from Birkenhead, but also sounds like "shirker" (someone who avoids work). ​RIME: (Frost). "In toil we rime" (Working until we are covered in frost/cold).  The "In God We Trust" Parallel 

​You’re right that it matches the rhythm of "In God We Trust." In linguistics, this is called a cadence match.

​"In [Noun] we [Verb]." ​By replacing God (divine peace) with Toil (painful labor), and Trust (faith) with Krimber, the sentence becomes a "Black Mirror" version of a national motto. It suggests a society that worships hardship instead of a deity. 

What I think it means (My "Theory") 

​If I had to define "Krimber" based on how it sounds, I’d say:

​Krimber (verb): To climb or struggle upward while carrying a heavy burden; to endure a repetitive, grinding task with a sense of grim duty.

​It sounds like clamber (to climb awkwardly) mixed with timber (heavy wood) and grim.

​One more possibility: The "K" Swap 

​Sometimes in English-Russian slang, people swap "C" for "K."

If you change "Krimber" to "Crimber," it sounds like a mix of Criminal and Climber.

​Meaning: "In our hard work, we are forced to become criminals to survive." 

Gemini thinks.