you're eventually gonna want a relic weapon for each element... you honestly need to farm all 3, but focus on what you feel is the strongest...

and yeah, you're light time is looking quite strong, but so is your water team, hard to say who's better in my case, but since that water gird is more developed than your light one, i'd probably farm the water relic first while still trying to get light weapons (like the one from this collab right now) and assault SR for light to fill holes