Academic writing is surprisingly hard. Distilling months or years of work into its essential ideas is almost as challenging (for me anyway) as the research itself.
Often it forces a clarity that only comes from writing ideas down in a way that's necessary to explain your results to your peers.
The process itself sucks, but the outcomes are often quite satisfying and rewarding.
I admire the old papers. "In this manuscript we derive XYZ from ABC and show that EFG still holds" followed immediately by something akin to "We begin by showing ... "
Nowadays the intro/motivation/problem statement / related work (citation tax) / formulation/<actual results> / simulations / conclusions / futurework format is just soul crushing.