Etsy allows two option types and no more
A product that is size, colour and material has to lose one before it will fit.
Etsy puts a hard cap of two option types on a listing. If an item is size, colour and material on TikTok Shop, it cannot stay that way on Etsy, so something has to fold: combine two attributes into a single option, or split the product across separate listings. Neither route is wrong, but the choice is yours and it is much better made on purpose at the start than partway through a listing run.
Etsy has a second rule that catches people, and it follows from the first more often than you would expect. Give two listings in the same shop one shared SKU and Etsy flags them as ‘Multiple same SKU’, which keeps sync switched off for the pair until each has a code of its own. Splitting a three-attribute product across several Etsy listings is precisely the moment somebody reuses a code.
So plan the fold and the codes together. Decide which two options each Etsy listing carries, then give every listing a SKU of its own, and the two rules stop working against each other. That takes an afternoon up front. Finding out afterwards means going back through listings that have been live and unsynced for a fortnight and working out what sold from where.