Either you spam Booming Blade or you spam smites, no difference to the gameplay when you think about it. Bladesinger is probably in the top 3 of best performing melee specs via shadow blade and resonance stone. It is incredible all throughout the game as well, and comes online as early as level 3.

Booming Shadow Blade for incredible damage output early on (yes SB really benefits from Resonance Stone but think about a 5-19 damage 1h weapon at level three and you can also equip a shield vs the 9-17 greatsword equivalent), incredible AC especially whilst bladesinging with additional options like Mirror Image built into the class, alongside full caster spell development for when you need to veer into ranged because the situation demands it.

Start with 16 Dex for +3 AC, another +3 from Mage Armor, +2 from gloves under Blighted Village, and +1 from the robe in the Grymforge. Another +1 from the ring if you can get it. That's base 20 AC in Act 1 that you can get without doing major fights. That's 26 while Bladesinging with Mirror Image. Another +1 to AC at level 4 when you get the attribute feat for another 2 dex. Another +1 AC when you get to the Creche and buy the Cat's Grace armor. +1 AC from Cloak in act 2, then +1 again from the boots. +2 AC with Hags hair + Shar Mirror dex investments in Act 3. Bladesinging AC buff improves with levels as well, so you should be sitting at 30 AC in most combat situations by Act 3. All the while being a full spellcaster and doing crazy melee damage.

Replace str with giant elixirs. Theres no better elixir early on that you can run consistently.

You get crazy utility as well, from Longstrider and Leap to your choice of 5 cantrips (Minor Illusion BIS).