With your high-end quality build BRYSTONs their audio performance will improve with better power cords.Why? They are built like tanks with robust power supplies.
You kinda nailed it wherein your any better / quality build PCs still plugged into a junk cheap power strip is largely a huge limiter, dare I say, a waste.
budgets always matter … sure … but IMO your budget needs to roughly double for three to four units that will include any quality budget strata power strip equipped with hospital grade plugs and fed by a quality gauge cable.
At an entry level price point for pre-owned PCs, ..say $150-ish, then its generally a “just pick one of ‘em” exercise without major performance variables between your many choices. A dedicated power line is intuitively something to plan for L-T, after which upgrades with matched performance tick-ups can be considered.