With how Google is; flips and flops like the weather, I don't think anyone can ever be, 100% finished.
However in answer to your question, Michael... I can't do anymore than I've already done.
I've tweaked the server, its software and that side of things. That's in addition to tweaking, optimising and in some instances deferring *.js & *.css coding.
Audited the plugins used, only a handful to commence with. Of those, I've managed to slash a further 2, bringing that number down to 5 plugin in total.
According to Google's own page speed test, Mobile score is 98, and Desktop is 99. That's ample in my book.
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Compliance: a code word for control
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Do the right thing, even when no one is looking. It's called integrity.
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