Use the research function it has been discussed A LOT.
Firebolt leaves a fire surface that deals 1d4, the spell deals a total of 1d6+1d4 making it better than a 1d10, the problem is the majority of people (me included) don't want it to leave an elemental surface as it makes it too strong and feels too much like DoS2.
Yup, it has been discussed to death at this point. But the thing that baffles me: Why are they trying to reinvent the wheel? If you want to adapt 5e and make BG3, just do it. Stop trying to shoehorn DOS2 elements into the game and just make a D&D based video game.