Hi semi crossbow enjoyer here. Starting from level 1 until around act 3, you can use the rampart raptor crossbow. It has a mechanic that makes the crossbow have infinite ammo after reloading. You still reload but way way less than normal. When this weapon gets weak, you can transition into last lament. It was broken last season, not sure how much it could work right now. You use hp to get ammo and not really reload. Not sure how much you can sustain it now, but supposedly with enough leech and or maybe atziris acuity(i think?) you could sustain the hp cost. If you don't want to try last lament you and/or you need something else before you transition to this, you could use permafrost bolts and fragmentation rounds setup on different weapon sets. You would also need shard scavenger. Shard scavenger is a spirit gem wherein when you cause an immobilization, in this case freeze with permafrost bolts, consume it then with fragmentation rounds, you will have a duration of unlimited ammo. The downside for this is it's on a cooldown, but not exaclty a cooldown. The length of the buff and the 'cooldown' are tied both tied to skill effect duration(iirc) and you would have to choose whether you want more procs of the unlimited ammo, or longer durations of the proc of unli ammo.