Reduce render delay first contentful paint element

Hello,
I am trying to reduce the render delay of my largest contentful paint element which is 70% of LCP.
I have enabled the “defer Javascript loading” settings on Layerslider
I have also enabled the following on WP Rocket.
-remove unused css already enabled
-Load Javascript deferred enabled

What do you recommend me to do to reduce the render delay of the following element?

Many thanks,

Modern 2-bed flat with parking for sale in Maida Vale London W9

<img fetchpriority="high" decoding="async" src="https://wiserockproperty.com/wp-content/uploads/2024/07/Slider-Winterton-H…" class="ls-bg" alt="Modern 2-bed flat with parking for sale in Maida Vale London W9" data-attachment-id="31671" data-permalink="https://wiserockproperty.com/slider-winterton-house/" data-orig-file="https://wiserockproperty.com/wp-content/uploads/2024/07/Slider-Winterton-H…" data-orig-size="500,350" data-comments-opened="0" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;…" data-image-title="Slider-Winterton House" …>

• This topic was modified 50 minutes ago by murielzs.

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