Improved Spell Sniper

Prerequisite feat spell sniper

Before you make a spell attack, you can choose to take a -5 penalty to the attack roll. If the attack hits, you add +10 to the attack's damage.

Spell Artillerist

Spend one charge as a bonus action as well as take a -2 penalty to your AC to make your next damaging spell have an effect.
For damaging spell attacks you get advantage on the attack roll.
For damaging spells that cause the target(s) to require a saving throw a number of targets equal to your proficiency modifier have disadvantage on that saving throw.
If you used a higher spell slot than the spells level to cast this spell or used sorcery points in casting this spell, on your action (or bonus action) until the end of your next turn you cannot expend any spell slots (cantrips only). You can still cast spells as a reaction though.