Has he ever deflected a multitude of projectiles or explosions?
Any Imperial Privilege Users, who can literally gain any skill in Fate as long as it isn't unique, although individual users may have specific limitations but none that disqualify them from gaining martial art combat abilities. Chiron has a similar ability to that as well with his skill Divine Gift of Wisdom, although his is slightly different from Imperial Privilege. Red Hair is a master of every martial art there is, and you can drop him into any situation or combat domain, and he would have a martial art to respond to it. Air Combat? He has some martial arts for that. Underwater Combat? He has some martial arts for that. A totally new and unknown enviroment? He has some martial arts for that. Keep in mind, Lancelot is superior to all of this skill wise.
Yeah, and Lancelot scales above people with better forms of reactive evolution and abilities that are just flat out better abilities that reactive evolution. Go look at the list of servants with Eye of The Mind (True), Eye of The Mind (False), Clairvoyance, Protection from Arrows, etc. and ask yourself if these servants are some incredibly high tier servant within the Fate series. Those that are, are there for reasons other than their precog. Its an incredibly common ability within Fate, and many main character servants have them, so basically any servant that can contend with the main cast has the ability to deal with it. Archer EMIYA and Saber are both users, so any person who can engage in combat with them (See, basically every single servant in the whole franchise) is able to deal with precog
Servant regen should heal the joints. If Lancelot realizes his opponent is getting stronger with every strike, then he isn't gonna **** around. He'll go for the head and try to finish it asap. If he does try to go for a more drawn out battle, then that's where the Jet and artillery comes in