Generally speaking, it would be best to not overlap features related to specific aspect of optimizations from multiple plugins.
For example, if you are using WP Rocket’s image optimizations, such as LazyLoad and Add Missing Image Dimensions, I think it’d not be advisable to also activate the same kinds of optimizations in Performance Lab.
Both plugins are analyzing pages to apply these kinds of optimizations in intelligent ways. For example, determining the LCP image for a page and preloading it, not applying LazyLoad for images above the fold, etc.
If the same optimizations are applied from multiple sources, it’s possible they could interfere with each other in some way.
@joejoe04 Good answer. That’s right. You should avoid having multiple plugins trying to do the same optimizations. Fortunately, the Performance Lab feature plugins are each largely focused on solving one specific set performance issues, so it should be relatively easy to pick and choose which plugins to activate based on the features any other active performance plugins provide.
