Quick Question About Selling Old Items

Possibly a stupid question here.

I was recently looking into selling a few old anime figures I have on mercari or other resale sites/store (only two, but both fairly pricey ones, one sells for around 50,000 yen resale) but was warned by a friend about it potentially causing issues with my visa/zairyuu because of the yen amount received vs taxes and income regulations for foreign residents.

Does anyone know if this is true, or where I can read about it? Google keeps giving me results about tourists selling clothes at second street and things like that, can't find anything about resale impacting a zairyuu card or person who lives here.

Also, if I am reselling things how does that work with getting taxed? Would Mercari, second street, etc. automatically take care of things? Would I have to file some kind of income report?

Thank you

by Correct-Sir-6837