I've yet to actually lose a battle. I just meant a super effective or really strong moves can take someone out of commission (i.e. as much as I like Breloom, his defenses & speed are pretty meh). Sans good IVs & EVs, I imagine it'd be a tough time when the NPCs are beefed up like this.
I would definitely recommend learning about IVs & EVs. I'm still on Umbra Moon, but my team is full of ideal IV/EV trained Pokemon & despite walking into most battles 7-10 levels above, they can still get their s**t pushed in sometimes.
Didn't see anything on his profile, but figured I should ask just in case: has Dio (or someone else) made a similar rom for DS Pokemon games (i.e. HGSS)?