Angelic Smite- feels redundant with default Volos aasimar racials (1 minute add level in radiant damage/Necrotic for the fallen)

Wrath of Heaven feels just right.

Flying Ace is interesting, would that include concentration checks on the spell?

Oceans Champion is busted by half. Make it last a minute and allow you to grant yourself advantage for 1 turn during that minute. It’s like Vengeance Paladin Channel divinity but over 9000.

Bestial Might- Wild Hunt Astral Self Monk. Advantage on all 4 or 5 or 6 of your attacks for 2 minutes per rest? Sign me up.

Pneumatic arms- bonus action to “charge” for advantage on checks, reaction to get advantage on saves. The rest is fine as is.

Durable is probably too good for most games as slashing tends to be King in melee or piecing if you stay at range.

Cardmaster-does the Expertise apply to attacks made with the cards?

Origami’s is an awesome feat and let no one tell you any different. I have a race of Shikigami in my Tiny Heroes supplement but their Origami is much stronger. Give it a look if you like.

Magic Artillerist looks fun but the limit on targets and damage scaling is really bad.

Martial Strength either does nothing or breaks the game. Dueling fighting style with a great axe seems much.

Last Stand- I’d make this a two stage feat. Boost the listed benefit even higher, allow it to be triggered at half HP if desired, but becomes another feat or the attribute bonus after you’ve used it.