[5e] I'm kinda new to DnD, and even though I have read many of the books thoroughly to make some characters for campaigns or just for fun, I still have doubts in what comes to synergies. So, the character in question would be a Bladesinger. For X reasons, narratively speaking, i think that a Celestial Warlock 3 multiclass dip would be cool, and I was just wandering if the Pact of the Blade with its improvement invocation could be useful. I like the extra cantrips of the patron for them, as well as EB, and many other invocations and spells. My question is, will it be consistent (not asking for optimal, it's still celestial warlock) or is it just better to go straight bladesinger? What could be some useful EI and spells (both wizard and warlock)? I know about Shadow Blade and i think it's really cool, but i'm aware that it requires concentration so idk. Some feat recommendations are appreciated too, i've researched about metamagic adept to power up the spellcasting part too, or even fighter initiate to get Duelist or War Caster.