I suggest Artillerist to at least level 5. That gets you Arcane Firearm; spell focus and damage booster to spells (including cantrips), but also a firearm usable as any other firearm, but still with whatever the wand/staff/rod you made it out of available too. In your case, a musket, which can be used with the Sharpshooter feat. Get yourself the Archery fighting style for +2 damage.

The Eldritch Cannon scales out fairly early (until 9th anyway), but as a bonus action, you always have a second attack.

Two level dip of Fighter for Action Surge, if you don't mind thinning spell progression. Going to 5 levels for Extra Attack may not be worth the spell progression loss.

An idea: Swords Bard's Blade Flourish works with ANY weapon, gets Extra Attack at 6th, helps with spell progression. Only the Artificer spells can be boosted with the Arcane Firearm, but slots are slots.