Good Score on GTMetrix, but not good enough on Google PSI

Hey all,

Like most website owners -- I am diligently working on preparing for Google's CVW update in May.

I have fixed my infrastructure and hired a Developer to fix most stuff.

His work has helped me get the GTMetrix score to almost 100%.

My results for Google PSI Desktop are really good -- close to 100%.

But Mobile is still lagging. I am still having issues with LCP.

50% of my traffic is mobile.

Should I be worried? Or am I over-optimizing? I am really concerned about the impact of the May update. I lost some traffic in February due to Google updates.

Any suggestions?