Canonically erza doent have an ego problem.
Erza was right next to laxus when he nuked ajeel. She knows its nothing impressive.
Wahl was very weak, and pis and cis in laxus vs wahl fight was erza vs koyoka level, so not impressive or as impressive as the crap erza vs irene was
He got around that hax because he is weak
Laxus was actually buffed. Erza wasnt
Laxus wasnt suprised by erza strength, erza was suprised by laxus strength. This cannon now, its laxus who improved the most.
Erza had one buff, a small buff, that dragon seal. It most likely slightly increased her attack power
Her using natsu and gray magic, was just one attack. After that she became serious and used belserion sword against laxus. You can see that sword when erza and laxus are exchanging blows and both are serious.
Meanwhile laxus already knew non serious erza required red lightening mode, which is actually a huge buff. Add when erza used fire and ice sword (while holding back) it drew alot of laxus blood. Which buffed laxus even more. Laxus red lightening mode increaded his attack power and might have increased his speed as well ( lightening body was red)
Serious erza was fine against this buffed up laxus with just dragon seal. Her dragon seal with blumblatt was strong enough to stalemate laxus most strongest move in his buffed up red lightening mode. (No fire and ice swords required)
Erza buff
Dragon seal (nothing about huge power change is mentioned)
Belserion swrod
Fire and ice sword (only one attack when non serious)
Laxus buff
Red lightening mode (power increased alot)
Bleeding buff for red lightening mode (even more increase is mentioned)
I guess alot of people have problem now. People always tbought portrayal wise laxus was above erza by alot. Apparently he wasnt even above her, atleast in erza point of view. And all feats people use to hype laxus a tier or so above erza, happened when erza was around. Those feats were apparently not suppose to show laxus above erza at all.