This is not true!! Don't let the doom and gloom get to you.
Firms take holistic approaches to applications, sure there may be some firms who put a stronger emphasis on grades but many firms do not. I secured a TC at a top US firm without ever even getting a first in any module and only one vac scheme before

. One example doesn't exemplify the whole industry, I know the application cycle can feel rough but quality applications are worth it- at the firm I got my TC I spent ages researching them and was truly interested by the work they were doing, and it shone through and made a difference.
Quality applications and a genuine interest in the firm do actually make a difference, despite how hard that might be to believe because of how alienating the process feels.