For the same reason - traditional look -  on my NE Dory I used Hempex from R & W rope.  Extremely satisfied.  Looks good, wears well, is pretty easy on the hands (even better than synthetic double braids), splices & etc. just like traditional hemp (or whatever) 3-strand, comes in many sizes and perhaps almost best of all, ends can be melted to prevent fraying - so no backsplices, tape or whipping required.

I used all brass, bronze or wood hardware and fittings everywhere on my boat.  The only stainless or plastic anywhere is the stainless rudder gudgeon/pintles (and I subsequently saw some bronze ones that would have worked had I found them sooner).  I tried to get traditional blocks, but due to expense of fancy wood blocks these days (and I'm not sure small sizes are available) I opted for Tufnol blocks. I was even able to find a nice Tufnol auto-ratchet block for the main sheet.  Had to jump through some hoops to get it from a UK e-bay person that didn't do international shipping, but looked up a local junk shop in the same town and had them do the transfer/shipping.

I don't have familiarity with alternatives, but I do recommend the Hempex.

https://rwrope.com/products/hempex-the-synthetic-alternative-to-hemp-rope?variant=14089329573941