Where each structure wins.
Open or keep the 401(k); replace the holdings. Set the contribution rate to capture the full employer match (the match itself is permissible compensation). Inside the wrapper, allocate to halal-screened funds and avoid the default target-date glide path. For specific fund choices, see /retirement.
Verdict above is editorial. A Mufti Saad signed verdict replaces this when corpus content covers the comparison.