I disagree... You don't actually fight any mind flayers or dragons, only imps which as far as I know are relatively low level challenge.

I expressed my opinion about companion levels many times, but the short version of it is - they are not as powerful as they claim to be or want you to perceive them.

Larian's Biggest Oversight, what to do about it, and My personal review of BG3 EA
"74.85% of you stood with the Tieflings, and 25.15% of you sided with Minthara. Good outweighs evil, it seems."