This seems to work with 365:

Formula: copy to clipboard
=MAP(A1:A6,B1:B6,LAMBDA(xa,xb,LET(a,xa,b,xb,tsa,TEXTSPLIT(a,";"),tsb,TEXTSPLIT(b,";"),TEXTJOIN(";",,MAP(tsa,tsb,LAMBDA(ma,mb,TEXTJOIN(";",,ma,mb)))))))


You will need to remove any trailing semi-colons.