At this point, all isekai should start with "Yes, everything is copied from all previous isekai manga so here's 2 pages to summarize:" and just the usual generic info about how human nobles are bad, guilds are ranked F-S,etc...
I can't help but feel this big bad monster will be a peace of cake for our hero since he is one of those super-human killing machines right out of THE Monster Hunter™
One of the most realistic reactions I've seen in an isekai so far in a MC.
You are happy to save someone.
You are also cringing from using your extremely expensive medicine.
You dither, regret, compare the alternative, and then accept that it was the right thing to do.