true , power supply is the most improtant part of the build and can be kept for longest -
but if i´m thinking long term i would certainly not settle down for a 750w unit ,
these days i would honestly go for a 1 000w unit (850w at minimum)
(even if my current system doesn´t necessarily need it) .
especially when the situation on the market is such that a price difference between good quality 750-850 or even some 1kW units are almost non-existent (negligible) .
and the efficiency of 850w-1kW gold units at 20-80w load improved a lot in the last few years .
dark power 13 750w is not exactly "top notch" (very good unit yes , but there are others that do the same or better job for lower price)
also DP 13 is just too overpriced : $200+ dollars for a 750w is just a no go ...
my picks for OP when it comes to price/performance ratio would be for example
SeaSonic VERTEX GX-1000 80+ Gold (89% efficiency at 10% load)
ADATA XPG Core Reactor II 1000 W 80+ Gold (81% efficiency at 20-80w load)
(that would be a recommendation to someone who lives in the US ,
in my region it would be corsair RMx (2024) since these units are priced competitively here and are available)
both of these units are cheaper and more suited for any future upgrades you might throw at them .
if you don´t want to go too overboard in terms of price you can settle for a 850w good unit: (they exist even around $100-120 price tag)