Is it an RCA to RCA cable, or a DIN from tonearm to RCA? easy to find and use long RCA to RCA. A bit harder to get a long DIN to RCA
Lots of people believe keeping phono cables short is important.
I ordered a custom 8 ft DIN/RCA cable for my 3rd arm from Pine Tree. Compared it to it’s OEM short cable, heard zero difference.
I would try your TT temporarily placed to use a short cable, then use an inexpensive long rca cable, hear any difference? Don’t forget some slack to turn equipment to have access to the rear jacks.
Then, buy a higher quality cable? Based on the Tonearm maker’s recommendation, I bought a high end Ortofon phono cable, didn’t hear any improvement than inexpensive cable I was using while awaiting delivery.
btw, if you have no choice, you have no choice!