The most useful tool is a magic bow, bracers of archery 5e or crossbow. (up to +3) Bracers for Archery 5e give you +2 damage and proficiency if you don’t have it. Magic ammunition (+1-3) can also be purchased, but each can only be used once. You can use this in conjunction with a magic bow/crossbow or sling. However, spell precedence means that you cannot enchant the same weapon twice. You will need a DM to rule whether they can be added together, whether a magic crossbow/sling counts for magic for overcoming resistances, and whether ammunition is required for that.