A good example for the sometimes conflicting relationship between epistemic rationality (e.g. updating on all relevant pieces of information you encounter) and instrumental rationality (e.g. following the optimal route to your goal (=winning the match)).

In principle the information regarding your opponent's skill is very useful, since you'll correctly devote far more resources (time) to checking for elaborate traps when you deem your opponent capable of such, and waste less time until you accept an 'obvious' mistake, when committed by a far inferior opponent.

However, due to anxiety issues as the ones you laid out, there can be a benefit to willfully ignoring such information.

Also, per your wish,

• superior opponent: confident
• slightly superior opponent: confident
• slightly inferior opponent: neutral
• inferior opponent: nervous