He's not weak. If anything he's lane bully and late game hypercarry but has a weak mid game.
watch LS coaching.
https://www.youtube.com/watch?v=1p0vaNyFqEQ&t=8s
You'll see has pretty good shove power at lvl 1 when you learn how to place his soldiers, I don't think any midlaner shoves quite as quickly as he does early game except for maybe Aurelion Sol.
He gets lvl 2 quick and allows for a W-Q-AA-AA-TLD proc, that chunks them to about 60% then you just move back immediately because you're on cooldown.
You win in two cases:
- trade and retreat immediately using range advantage or
- extend the fight while they are on cooldown autoattacking with your soldiers. You're a DPS champion afterall.
Focus on your csing mostly, and theirs. You see they are going for a creep fire a soldier in that direction Q-AA-AA- TLD.
You outrange Orianna any attempt to Q-W is obvious. The same way you can't autoattack with soldiers outside a certain range is the same way she can't move the ball with Q properly outside a certain range. If she's walking up Q-AA-AA-TLD and kite back (making sure that you're attack moving), then just push the wave and force her to choose between csing and attacking. Believe me she doesn't have enough mana for both early game.
Barrier is your best friend. What happens when you shuffle an enemy burst champion they use their burst combo and you pop barrier? You win the fight and get a kill. once you block the majority of the damage with barrier it will probably be 5 seconds till their next ability is off cooldown. All that's left is for them to eat several autoattacks (5 seconds worth) from soldiers as they try to run away. Same goes for the laning phase if they get greedy for the thunder lord proc. They are on cooldown keep attacking your autos hurt more than theirs.
As for Viktor, just don't pick Azir into him. His damage is high instant, you can't avoid or juke it like Orianna or just use range to keep away cause he has decent enough range with E. You'd just want to avoid trading as much as possible in his case, and farm/scale up (i've asked about him in particular on AzirMains)