I've never tried something like sushi. Nobody in daily American English conversation would use the word akin. Although everyone would understand your point. Keep in mind Sherlock Holmes, the original, is about 100 years old, some of the phrases will not be common today.

Americans, and I can't speak for the other english speaking countries are extremely informal. The only formal setting nowadays is something legal, either a legal setting or an official contract and/or document. In regards to sushi or food in day to day life no one would use the word akin. A native speaker would 100% know the word which means it is not super uncommon. Most likely usage would probably be more of an educational setting. In chemistry class this metal is akin to this metal. Or this philsopher is akin to this, etc. Conversational American English like comparing foods, people, places stick to like or similar.

"I've never tried something akin to sushi" "My mom is akin to my aunt" están bien pero muy formal "I've never tried something similar to sushi" "My mom is similar to my aunt"