You are all exaggerating and downplaying things to your preferences.
- No, Escanor didn't let Estarossa attack him, that was a surprise attack and he obviously felt pain, we even saw him bleed him from a single punch. Galan would have never managed to do that.
- Estarossa was not serious when he punched him, same for Escanor when he answered with his own punch.
- Estarossa decided to get serious after taking the punch. Starting to use his sword and it was the same for Escanor, he even said it.
They were evenly matched until Escanor's huge power up at 11:00 or 11:30. And before that moment, Estarossa had the advantages because has he stated, he was able to reflect all of his physical attacks and his Magic was stronger.
I am quite sure that Escanor at his peak never fought Meliodas at full power and already stated why I think Meliodas would win. Escanor overpowers his opponent with his absurd raw stats(strength, speed, durability, stamina) and Sunshine, he is the strongest as in "The one with the highest PL". All his victories were like that, he won because his PL was simply much higher than his opponents, which is the reason why he could not beat Estarossa as quickly as the others, they were evenly matched until his last surge of power.
I think at his peak he probably has the highest PL in the series. However, I don't believe a single second that his PL is much higher than Prime Meliodas or the Demon King. So, even if at his peak he was at 100K and Prime Meliodas at 95K or something. I don't believe he would win against Meliodas.