For a dedicated hi-fi strata 2-channel system driven by quality build electronics into quality build speakers, then …yes …. stepped up speaker wire upgrades do matter.
For the usual home theatre multi-channel system driven by the prevailing mass-marketed multi-channel AV preamp/ processors, or the AV multi-channel receivers ….. it can be and usually is a waste of money and worse.
Firstly, the 7.1 to 11.x multichannel audio soundtrack is largely an artificial manufactured soundtrack that is limited and or incapable of any improved soundstage performance,
Secondly the usual multichannel upstream HT components simply don’t have the audio performance capabilities to compare against the said 2-channel high(er) end system.
Thirdly and most importantly, concealing any speaker wire behind the walls requires a rigid fire code cable rating or you void your house insurance policy in case of fires 🔥. These types cables are specifically rated and labelled as such , and invariably these are entry level budget strata model offerings that come off bulk cable rolls.
FWIW, I have a $20K HT 7.1 system in my mancave along with 3 other 2-channel systems ranging from $1500 to $5000 to $50,000. I have progressive $$$ stepped-up cables in the last two systems , and I use quality build (at their entry level price point strata) BELDEN speaker cables for both the HT and the budget 2-channel rig.
the HT speaker cables were the largest gauge fire-rated BELDEN available now behind the walls driving a $10K+ MARTIN LOGAN speaker system. and $10K of upstream electronics, They work great for a HT system .
Caveat emptor, sir and don’t fall for money poorly spent