Voyager Step-In Air Dog Harness - All Weather Mesh, Step in Vest Harness for Small and Medium Dogs by Best Pet Supplies https://www.amazon.com/dp/B092JRRLJP/ref=cm_sw_r_cp_api_glt_fabc_V5X8EKCCEE85W55DR5NF?_encoding=UTF8&psc=1

just bought this in xxtra small for my tiny skinny chi! I think they even have an xxxtra small. it’s a great sturdy harness that goes on like a bra and clips on the back

hopefully it works for you too.