Are phanteks psu extension cables safe?

Got a powercolor reaper 9070xt a few days ago and absolutely loving it. However it doesnt look super clean due to the two 8 pin connectors both having pigtails so i was thinking of getting some cable extensions to make it look nicer and the phanteks psu extension kit is on sale so im considering it, but ive read a lot of warnings about extensions creating instability, causing crashes and even frying cables, but ive also seen people saying they work great so im left pretty confused. Is it safe? Will i see any performance or stability penalties? I want to mess around with undervolting it, would extension cables impact that? My psu is the coolermaster mwe gold v3 850w non modular.