The answer to this is very simple. It's Kefla.
This might seem a little hard to believe at first because of the final beam exchange where Goku, Vegeta, Gohan, Freiza and 17 powered up and gave it their all. However, here's my argument for the same:Whether Goku is stronger than Vegeta and Freiza in his blue form or vice versa is very debatable but either way I think it's fair to state without any shadow of a doubt that, Goku SSJB + Kaioken * 10 is stronger than all the 5 fighters together. We know the Kaioken multiplies Goku's power as we see Hit state that Goku's power has doubled, tripled, quadrupled, during the Universe 6 vs Universe 7 fight. Hence, Goku SSJB + Kaioken * 20 is without a doubt, way stronger than the 5 of them combined.
During Goku vs Jiren, when Goku used Kaioken*20 and charged towards Jiren, he used his Eye attack which in my opinion is one of his strongest moves consider he only bothered to use it against a powered up Goku twice, against Hit after he was trapped in the Cage of time etc. This attack was strong enough to flick away SSJB+ Kaioken * 20 Goku like it was nothing. After Goku attained the Ultra Instinct and Charged towards Jiren, we see him being able to not just dodge, but also block and push back these attacks as we see Goku pushing Jiren back. If Goku was only dodging the attacks, he wouldn't have pushed Jiren back. When Goku used the UI against Kefla, we figure out that Goku had grown stronger and powered up even more. Whis also remarked that UI Goku's attacks in aren't that effective (This was in his powered-up state hence his attacks against Jiren would've very likely been even weaker). Still, Kefla was strong enough to take hits from UI Goku, get back up and put up a fight. This shows Kefla in her SSJ2 state is way stronger than SSJB + Kaioken * 20 Goku and hence superior to Anilaza. Whis stated that SSJ Kefla's power was comparable to that of the Spirit Bomb used by Goku against Jiren. The spirit bomb is certainly very comparable and might even be stronger than the combined beam attack from the 5 remaining warriors. Let us say for argument sake that it is weaker than the combined beam attack. The power was compared to SSJ Kefla. SSJ2 Kefla is a lot stronger than SSJ Kefla as the SSJ2 is a 100 times multiplier while the SSJ is a 50 times multiplier. So it is very obvious Kefla's powers again surpass that of Anilaza. Even though Anilaza had the upper hand in the beam struggle until Android 17 broke the energy reactor, the Universe 7 fighters were holding their own and it wasn't completely domination.Kefla's potential and Saiyan abilities make her stronger than Anilaza. Goku stated that he senses no limit to her energy and Kefla certainly had a lot of potentials and if she hadn't had to fight a god-tiered fighter like UI Goku, she would've very likely had more time to draw more and more of her power and probably even attained the SSJ3 transformation. Also, Saiyan's attain Zenaki Boosts when pushed to their limits. The final attack unleashed by Kefla against UI Goku was indeed a lot stronger than a basic SSJ2 attack as Cabba remarked that her power is growing exponentially.