Fight scenes come down to pre-planning, choreography and skill of the performer.
Note that movie fight scenes often take a month to create. I'm not familiar with the movie you linked above, but, if you know the "single take stairway fight" from Tom Yung Goong/The protector, it took a month to choreograph and rehearse and two weeks to shoot. On a Jackie Chan movie Jackie has said it usually takes an entire day to shoot 5-10 seconds of fighting.
Film Riot has some tutorials on shooting and editing fight scenes, but, the bottom line is to shoot a kick ass fight scene you'll need actors and a choreographer with physical skill and lots of rehearsal.
There isn't a "make fight scene look realistic" effect. The reason why everything I said and linked was about shooting the fight scene is because that's where the realism comes from. It's all going to come down to the performance of the actors, the camera angles you choose on-set, and the basic editing of the footagr.
As far as "effects" go, one of the videos I linked used masking to extend an arm that's a little too far away. That's an emergency patch. You could maybe use rate stretch or Speed/Duration to speed things up a bit (shooting for undercrank is a discussion of its own), but, yeah, a good fight scene is all about how you choreograph and shoot it. Sorry if that's not the answer you wanted, but that's the situation.
As far as editing goes, I don't think anyone can give any meaningful tips on that without seeing some footage. An editing class I had in film school started with a fight scene from a TV show - we all got the same footage, and 28 students cut 28 different looking fight scenes.
See, if you have truly skilled actors, you might be able to shoot and use long takes showing off the moves. If your actors suck, you might be cutting on every single punch or kick to hide how bad they are. We don't know without seeing footage.
The best editing advice I can give is to find some fight scenes you really like and study how the camera is used and how it's edited, but, the thing about editing is, if I gave you, me and 10 other random people the same raw footage we'll all cut it differently.
Ok, I'll talk about undercranking - speeding up footage - a bit.
This is tricky for multiple reasons. First, you can't speed things up too much or it'll look cheesy and fake. Second, Hitfilm speeds and slows footage by duplicating or skipping frames, so, if you don't shoot at the correct frame rate for your speed up, your footage will look jerky or stuttering - notice that, once again we're talking about how you shoot, not how you edit, because a good fight is all about how you shoot it.
So, shooting undercranked... Well, first we have to know the frame rate you're editing in. I'll assume 23.97 fps at the moment.
Next, we have to know the frame rates your camera can shoot - if it's a phone you'll have 24, 30 and 60. Maybe 120 or 240. Most of these are multiples of 30. If you have a camcorder, DSLR, Mirrorless or Cinema camera you might be able to switch between shooting NTSC or PAL. NTSC should give you 24, 29.97, 60 and maybe 120. PAL will give you 25, 50 and maybe 100. You MIGHT even have 48.
Now you have to do a little math. If I'm editing at 24 fps, I need to figure out the proper speed so every frame of my video matches a single frame on the Timeline - or else the video will judder or stutter. This means my camera footage needs to retime to a multiple of my frame rate.
So, if I've shot at 30 fps I need to speed the footage up to "48" fps. For this I divide the target frame rate by the camera frame rate.
48/30=1.6 or 160% if I shoot at 30fps I need to put the footage on the Timeline, right click, select Speed/Duration and set the speed to 160%. Any other value between 100% and 160% will cause stuttering as frames are skipped over.
160% will probably look fake.
What if I shoot at 50 fps? Well, if I time for 48 fps that's a slowdown, so now I need to time for 72 fps (24*3). 72/50 is 1.44 or 144%. Still probably fake looking.
What if I shoot at 60? 72/60=1.2. 120%. Now we're getting somewhere. A 120% speed up will probably look pretty good. AND if I've shot at 60 I can ALSO do a slowdown to 40% (24/60=0.4 or 40%). Now I've got some slightly sped up fight and I can snap to slow motion for emphasis.
But, yet again, this still comes down to planning before shooting so the speed up effect looks right. Again, a good fight scene is all about how you shoot it and how good the actors are.
Final example. Watch Iron Fist on Netflix and see how bad the fight scenes are when Danny Rand is fighting and his face isn't covered. Danny Rand actor Finn Jones didn't want to train and rehearse - the fight choreographer has hinted at this in interviews - and all Danny's fights look terrible because the actor suckes. Look at any of Colleen Wing's fights and they're way better because Jessica Henwick did the work to look good.
A good fight just comes down to the actors and choreography, and that's all before the edit.