You can try these Formulas using REGEXREPLACE:

=REGEXREPLACE(A1, "\s+\n", CHAR(10))

Or

=REGEXREPLACE(A1, "\s+($|\n)", "$1")

Also, try using REDUCE:

=REDUCE(,SPLIT(A1, CHAR(10)), LAMBDA(a,c, JOIN(REGEXREPLACE(c,"\s[^ ]*$",""),a,CHAR(10))))