I had recently seen the sequel again & Batroc's confrontation against Steve made me think over this.

Batroc did have some edge at first since he caught Steve by surprise & even as he lost the confrontation, it was the choreography.

The fluidity from which Batroc moved gave him still the fair chance to hold himself against Steve.

I feel no similar effort was made on Sam. Even as we see him deny the serum, I feel such scene could have helped communicate it more.

The serum helps so long as the person having it also possess the skills.
I remember the conversation was once over Sam to have the serum so he can prove himself better but the opening sequence from The Winter Soldier serves as the best evidence to stress only on technique.