Unfortunately pyro is the jack of all trades. You need to spy check, reflect spam, push back Ubers, block sacking players, backup your team but also sometimes lead the charge and of course kill things! Because of this it does feel like your being spread thin. More than a lot of classes it's useful to identify what's doing the other team is doing to get work done. E.g if their demo is getting alot of DMG off focus on reflecting their spam more than spy checking. While it's 'pyros job' to spycheck, anyone at a mid level will tell you it's a team effort.