LCP Issues affecting performance

Hey everyone! I was recently approved for Journey, and I'm thrilled to be here.

However, after installing the ad script, I've noticed a significant drop in my PageSpeed results. My desktop score went from 99 down to 81, and my mobile score dropped from an average of 75 down to 55-60.

Looking at the Lighthouse diagnostics, the biggest issue is a massive "forced reflow" (forced synchronous layout) caused by the Journey script calculating container sizes before the page finishes painting.

Here is what I have already tried to fix it:

1. Dashboard Settings: I have turned on all the "speed optimization" toggles in the Journey dashboard, but it didn't move the needle.
2. CSS Space Reservation: I tried to reserve space for the ads to prevent layout shifts and reflows by applying min-height: 275px and contain: layout paint to the .mv-ad-box class.
3. Why CSS failed: It seems the Journey JS dynamically injects inline styles (e.g., style="height: 350px; overflow: clip !important;") directly into the HTML after the auction. This overrides my external CSS, and the JavaScript execution itself still forces the browser to recalculate the layout, triggering the reflow penalty.

I know the "silver bullet" for PageSpeed is to use WP Rocket to Delay JavaScript Execution until user interaction. Because my blog posts have a large hero image above the fold, 100% of my engaged readers have to scroll anyway, so they would trigger the script immediately.

However, I've read all the manuals and FAQs, and I know Journey strongly advises against Delaying JS because it delays the ad auction and can hurt viewability/RPMs.

My questions for the community/support:

1. Is there any native way to fix this specific "forced reflow" JavaScript penalty without delaying the script?
2. Has anyone successfully used Delay JS on a site with a massive hero image (where users are forced to scroll) without seeing a drop in revenue?
3. Or is accepting a ~60 mobile performance score simply the reality of running premium programmatic ads?

Would love to hear how you guys are handling this balance between Core Web Vitals and ad revenue! Thanks!