The intent was to find those who are comparable and can compete in a duel. Obviously there will be beings and entities higher tier than Wizards, but such entities are not within the spirit of the OP. I'm looking for those that can compete on equal footing.
Assuming that both participants start in the same empty field naked save for their weapon of choice, it is basically straight reflexes.
Wizards are more durable than normal humans but not enough to remain combat effective after being shot a few times. Give someone decently skilled an AR-15 at low ready and put them against an average wizard at fifty meters and the guy with the AR will win probably 99 times out of a hundred.
Unless the wizards first, instinctive, response to a combat situation is to basically instant cast a shield or to apparate then they will be dead (or at least disabled) before they can get a spell off.
Now give that same wizard a shield hat and they would win that duel every single time as they get to flat out ignore the bullets while having countless methods of disabling the muggle.
Now take a wizard who is wearing a full body bodyglove charmed with cushioning and unbreakable charms, sewn out of demiguise fur so as to be an invisibility "cloak", wearing glasses enchanted like Moody's eye, charmed featherlight, silent, and with temperature charms so that their body is kept at the perfect temperature and the outside exactly matches the surroundings.
That wizard could casually defeat a great many sci-fi armies on their own.
If you are looking at society vs. society then the wizards get their more esoteric abilities.
As I mentioned before, an Unplottable charm is going to screw over virtually all non magical weapons even for high end sci-fi settings. When a location can't appear on any map it becomes
really hard to target that location.
Fidelius protected bases are just a flat out "I Win" level of security. The location is hidden inside a living soul and unless the possessor of the secret shares it then the location can not be found; period. How, as a society, do you fight an enemy whose bases, staging points, and infrastructure you can not locate or identify?
Apparition is, at a bare minimum, teleportation with a range measured in the dozens of miles. How do you fight an enemy that can simply pop past your defenses? In a very small area, sure. Pressure plates in the floors, physical obstructions, various sensors and automated defenses to identify and engage upon arrival, etc. But on any kind of larger scale? Detection, deterrence, and prevention is effectively impossible. And on a battlefield? Without a way to shut down apparition, you are fighting what is basically budget Nightcrawler.
Infiltration and interrogation? Polyjuice is a perfect physical transformation into anyone that you can get a biological sample from, and can be made by a 12/13 year old girl in a bathroom. Biometric security is virtually entirely worthless (gait analysis is about all that would work) and false flags become trivial. A wizard under an invisibility cloak uses Accio to summon a single hair from a target, potentially from miles away, and suddenly they are that person for all physical purposes for an hour. Imperius turns anyone but (perhaps) the exceptionally strong willed into
willing slaves and could apparently be kept up for years without issue. Capture someone and with a single spell you can have them willingly spilling their guts, or making whatever confessions that you want, or becoming a suicide bomber, etc. As little as a few minutes alone with
any individual and they can become a sleeper agent that you are only going to detect before they act out of character via telepathy or the like. Truth serum and legilimency also help with both.
A single adult wizard using nothing but spells/skills/items shown in the books/movies to be readily available could bring the modern world to its knees in a day or two. Apparition + Fiendfyre could have every city on the East Coast buring with sentient magical flames hostile to life. Imperio could have the PPD entirely compromised in a matter of days and then, suddenly, the Pres., VP, and entire cabinet is assassinated at the next cabinet meeting. Or compromise some to learn the needed schedules and then just put the entire top level of the executive branch under your control; and do it for multiple nations.