Lucci's biggest feat this chapter is not surviving G5's attacks. It is taking down Sentomaru with single attack. Iirc pre TS Straw Hats couldn't even touch him (same pre TS Luffy who already took Lucci down). Even in post TS, iirc Oda never clowned Sentomaru as hype tool to show Straw Hats' growth during timeskip. Means Oda still wanted to respect Sentomaru's portrayal.
One shotting him and Sentomaru admitting he wasn't cheap shotted is Lucci's biggest feat.
Surviving G5 isn't, G5 is that underwhelming.