Could I have played any street differently? How did he find this fold on the river?

PL Omaha 200
HERO BB (100BBs) [VPIP: 36% | PFR: 24.8% | AGG: 40.5% | Flop Agg: 47.9% | Turn Agg: 37.9% | River Agg: 42.2% | 3Bet: 9.1% | 4Bet: 16.7% | Cold Call: 20.7% | Hands: 2,743,525]
UTG (41.5BBs) [VPIP: 80% | PFR: 6.7% | AGG: 13% | Flop Agg: 10% | Turn Agg: 12.5% | River Agg: 20% | 3Bet: 0% | 4Bet: 0% | Hands: 15]
HJ (90.9BBs) [VPIP: 31.3% | PFR: 18.8% | AGG: 26.3% | Hands: 33]
CO (157.3BBs) [VPIP: 25.7% | PFR: 22.9% | AGG: 33.3% | Hands: 35]
BTN (111.6BBs) [VPIP: 25% | PFR: 25% | AGG: 41.2% | Flop Agg: 14.3% | Turn Agg: 66.7% | River Agg: 50% | 3Bet: 14.3% | 4Bet: 0% | Hands: 25]
SB (129.7BBs) [VPIP: 52.9% | PFR: 17.6% | AGG: 23.8% | Flop Agg: 33.3% | Turn Agg: 40% | River Agg: 0% | 3Bet: 0% | 4Bet: 0% | Cold Call: 50% | Hands: 18]

Dealt to Hero: 4 2 A 6

UTG Calls 1BBs, HJ Folds, CO Folds, BTN Raises To 4BBs, SB Calls 3.5BBs, HERO Calls 3BBs, UTG Calls 3BBs

Hero SPR on Flop: [2.34 effective]
Flop (16BBs): T A 3
SB Checks, HERO Bets 10BBs (Rem. Stack: 86BBs), UTG Folds, BTN Calls 10BBs (Rem. Stack: 97.6BBs), SB Folds

Turn (36BBs): T A 3 5
HERO Bets 22.5BBs (Rem. Stack: 63.5BBs), BTN Calls 22.5BBs (Rem. Stack: 75.1BBs)

River (81BBs): T A 3 5 K
HERO Bets 63.5BBs (allin), BTN Folds

Because 2-pair's not a good hand in PLO perhaps?

You gave BTN almost the perfect pots odds to draw to a FH or Flush and they missed. While they did improve to a better two pair there is now another 5-card hand (and all sets) that they lose to now, being the Wheel and Broadway.

You should be 'happy' you gave them the odds to call on the Turn and also make note that you may be able to bluff them off some Board changing Rivers in the future.

While you may get called by some opponents when they go from A3 to AK here, not everyone is a POW in PLO .. especially after you show aggression two streets in a row. It's actually a bad River for you but I'm not sure you would get called on a blank either.

There's a fine line for value in PLO .. everyone thinks you need to pot and/or go all-in all the time as fast as possible. Would you have brought this hand here if V snaps you off with a Broadway wrap?

Sometimes both Players in a hand can play correctly .. this time you were on the winner's side. GL

I'm not really a fan of your flop lead. I say that because I doubt you have a balanced flop lead strategy in this spot.