What is Better for farming Kaiba Lv 40 or Lv 30

Don't ever believe anyone says farming lvl30 is better than lvl40.

I advice you to wait until you have a consistence deck. Keep collecting white keys for now.

40. the chances are much higher for SR/UR cards.

I got 1 or 2 EC from losing. It is better to go for lvl 40 with bonus campaign. I think Kaiba has a better drop rate than Izumi and Odeon (maybe I am unlucky against them).
Try unhappy girl+Angel 07.

https://www.youtube.com/watch?v=BHOjZdoukjM

I farmed lv30 enough to tell you that it is totally pointless, it has way less chances to get premium pack and also drop table is bigger compared to lv40(trash tier chests and packs).

I farmed 2 enemies, 1 blue eyes, and 2 champion vigilance in 2 days just going for kaiba lv40 NO golden apples deck while farming lv30 took me 20 days to get 1 enemy, 1 champion and 2 blue eyes.

Hard LDs like Kaiba, Ishizu and Keith should be farmed only at the DA +1000 bonus campaign (which just ended), beacuse, worst case scenario you'll have at least 2 chests. I always go for the lvl 40 it is much better in terms of drops and the general outcome is always better in lvl 40.
For Kaiba I used Angel 07 (with Riryoku Field set), Vermin, Soul Exchange and busted my ass to protect my Kaiser Sea Horse (with halfshut, etaqua, econ, mirror wall) to use it as tribute fodder. Hunter of 7 weapons and mostly Conscription work well too

I got 3 copies of Enemy Controller from Lv. 40 in only 2 days, all from losses. There's no real 'better' way, it's all RNG in the end.

either way you only get tatsunoohigo

Lv 40 drop rate is better than Lv 30 but in the end it's always up to RNGasus. Sometimes you lost and get EC but in the other hand people win so much and only get bunch of crap