Speakers first, always. Only you have your ears, specific musical preferences in what sounds good and the environment they will live in.
Go with the objective of buying something you can live with for decades, source equipment will always be swapped as improvements or budget improve.
Had my first pair for 30+ years and cycled through 4 systems and they just kept sounding better.
As for GIGO, you can't drive great sound thru bad speakers but the opposite holds true. Great speakers will always sound good and make the most of the source.
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