break the back of

Verb

Meaning

(idiomatic) To complete the greater part of (a project).
I've broken the back of painting the shed – I'll finish it after lunch.

(Can we verify this sense?) To overburden (a person).

Source: en.wiktionary.org

As we break the back of this pandemic expect to see a lot more overt military assistance. Source: Internet

That's the kind of debt that can break the back of most small businesses. Source: Internet

The editorial argues “that it would be wrong to believe that all this will break the back of the students’ movement. Source: Internet

If Intel was able to own the Mac OS and make it available to all the OEMs, it could break the back of Microsoft. Source: Internet

I want to break the back of the gun lobby. Source: Internet