Starting This Off
This is gonna be a little tough to breakdown, but I'm going to use the assumption this is an Alex who went through all optional fights possible, but uses the canon ending of the game I have planned.
I'm going to work from him early training and then go up to mid way to training since context is needed.
One of the most important things to keep in mind is that this takes place hundreds of years in the future, keep that in mind for later.
Early Training
At this point in time, Alex has made it into the Monk's first step of training. For context there are three realistically obtainable ranks in the monk's order. Beginner, Experienced, and Graduated. But there is a fourth level called Enlightened, these last two don't matter too much besides the fact his potential is very rare in the verse and the fact he makes it to Enlightened at age 26 which took all the other Enlightened Monks almost 100 years to accomplish (though he still massively downscales from them since he is noted as being the least skilled Sage Monk)
Alex after becoming a beginner and passing the tasks needed to enter had to prove himself by completing a trial of selflessness that he must deem worthy. So he visits a man who saved his life before he joined the monks named Robert. Robert is a rebel that lives in a Bunker City that survived the nuclear apocalypse (Hence Wasteland Country) that is under thumb of a high-tech military police state. Robert and every other combatant (be it rebel or military) have cybernetic implants that allow them to do wacky shit.
Now in terms of skills, Robert (and every other rebel) have the ability to hack and create (combat mods) that amplify their combat skills but even the strongest ones made by Robert can only really master a single style of combat. Meanwhile the military have a special way of creating soldiers. All the military soldiers are clones of a single man who's mind is a blank slate, they then inject their brain with the best military grade fighting techniques they have ever had since modern time. This doesn't mean they know ALL martial arts, instead they know all the most lethal forms of combat developed to modern time and forward.
Additionally, when Alex initially tries to engage them with traditional martial arts he instantly gets overwhelmed since they've grown far beyond what the common martial arts the monks traditionally teach (Judo, Jiu Jitsu, Taekwondo, and Mauy Thai). This is only overcome when Alex uses the monk's uniquely developed martial arts that allows him to perform the Attack Reflection manuvers.
Alex completely dismantles and dominates the best fighting techniques they've developed and refined through conflict and simulation in hundreds of years with a incomplete and inexperienced version of the Monks' special martial art. He was able to completely deflect dozens of these soldiers firing automatic weapon fire at him. That's the best of his feats for his Beginner training.
Midway Through Training
For Alex's upgrade to Experienced ranking he then refines the monk's martial art in three years to a good degree, ranking above many other Experienced level monks but still not the best of this tier although he's doing something that takes a decade in one-third the time, this also means he's able to reflect grapples on himself since the monks spar with all their martial arts not just the reflecting one, so he's able to reflect grapples from Jiu Jitsu and fuel them for a Judo throw of the person who tried to grab him.
Alex for his next trial must investigate the disappearances of local people in a small remote village. It's revealed this village was built on top of a hidden scientific bunker filled with and leaking all kinds of screwed up experiments. From giant mutated spiders, to flesh consuming organisms, he's able to avoid major injuries by relying on that Monk Martial Art mentioned before.
This is where he does battle with the most guarded experiment here, Astra! Astra is a very dangerous and unpredictable foe to fight, she can create weapons from her body and if they graze you they can paralyze you for a short time. Alex from the spider webs, the flesh consuming properties on contact, to even the direct stab of Astra's paralyzing weapons can deflect it with his hands without having the added effects apply to him. Even though he's making contact their added effects (sticking to his hand, dissolving his skin, or injecting the venom) doesn't apply.
That is where his skill in his Experienced Tier ends, his really good skill feats are after training.
TL;DR
Very high level Judo, Jiu Jitsu, Taekwondo, and Mauy Thai, however his Attack Reflection martial arts upscale from that and upscales from those who effortlessly counter master level techniques from previously stated martial arts and the best of hundreds of years of combat simulation and evolution, and then upscales from those who are baseline good at the Monk's Martial Art.
