Perhaps the ultra-Orthodox could serve in supporting roles, rotating in and out to minimize interference with their religious obligations and preferences. In most militaries, for every combat soldier there are several logistical support soldiers, so this might free up men and women for combat roles. The argument that obliging the ultra-Orthodox to shoulder some form of military service would threaten the survival of the Torah seems weak on its face, given their number. The status quo is patently unfair. As for their reluctance to serve alongside women, one can only sigh.
@SnipeChrisSocialist2mos2MO
Having the Haredim do civil service in lieu of military service (an option in other nations with mandatory military service) has been proposed and rejected numerous times. They need the bodies in the yeshivas to get the maximum subsidy.