I've read the manga for Mash. It actually gets significantly better as you go on, but this episode is still great.
The studio have done a great job of adapting these episodes, and I'm hoping now people realise this character isn't a ripoff of Asta from Black Clover. Mash is very unique as a character, and this episode brought out his character more. But it doesn't stop here.
We were introduced to some more relevant characters this episode (look out for unique character designs) and therefore this episode is important to set the context. This is the beginning of when the show really begins, when Mash is at Easton, and I think the dynamic of the characters we meet is both weird and unique.
Overall, not exactly episode of the simulcast season (we do have hell's paradise) but fun, low maintenance and certainly not disengaging.