Is SEMrush flawed?

Hi all,

I'm learning some SEO and trying to analyze the traffic to our website. In GA4 the traffic over the last 12 months has been more or less flatline. However, in SEMrush, the estimated traffic trend is starting to look exponential. From June this year until now, we have almost doubled the ''estimated traffic" in SEMrush but in GA4 there seems to hardly an uptick in traffic at all.

Now, I understand that SEMrush is making estimates and not counting any actual data - but how on earth can the estimates be soo far from the truth? Unless I'm really missing something major, it feels like SEMrush is just spewing garbage bs at this point. I'd love to take the insights from SEMrush and present it to the rest of the company to show that our SEO efforts have been paying off, but GA4 is saying ''not so fast''.