You probably actually have a AF-S Nikkor 70-200mm f/4G ED VR lens (no one makes an f/1.4 70-200mm).

That's a very sharp lens.

Review by Ken Rockwell: https://www.kenrockwell.com/nikon/70-200mm-f4.htm
Review by Digital Camera World: https://www.digitalcameraworld.com/reviews/nikon-af-s-70-200mm-f4g-ed-vr-review
Review by PC Magazine: https://www.pcmag.com/reviews/nikon-af-s-nikkor-70-200mm-f4g-ed-vr This review notes slight loss of sharpness at the edges at f/4 when used on a full frame (FX) camera, which sharpens up very well at f/5.6. However, you are using the lens on a DX camera which naturally crops off those slightly soft edges and corners, using only the sharpest, central part of the lens.
Review by DXO Mark: https://www.dxomark.com/nikon-af-s-nikkor-70-200mm-f-4g-ed-vr-review-an-enlightened-70-200mm-lens-choice/

There are many more, all of which agree it's a wonderfully sharp lens. If you're getting poor results, probably you're doing something wrong.

It would be best if you were to upload one or more example images, demonstrating the lack of sharpness you're seeing... fairly large JPEGs with their EXIF data intact and using the "store original/Add Attachment" feature here on UHH. We could then look at the image(s) and info to give you much more helpful analysis.

Without seeing image samples, we can only guess. It may be that you're using too slow shutter speeds. Or maybe you have a poor quality "protection" filter on the lens or a dirty sensor in your camera, both of which can cause loss of sharpness. Or perhaps you need to calibrate the focus of this lens on your particular camera. Or maybe you're using the wrong AF mode or setup. There are additional possibilities, including that you have a "bad copy" of the lens (although this is probably the least likely cause).

We might be able to narrow it down, if we could see some examples.

I shoot a lot of sports... a couple million images over the last 15 or 16 years... and have two 70-200mm lenses: an f/2.8 and an f/4. Because this is one of my most used lenses (on crop sensor cameras like you), I bought the f/4 lens as a backup. But I have actually ended up using it more. I was stopping the f/2.8 lens down to f/4 or f/5.6 a lot anyway, to be sure I had sufficient depth of field when subjects were close. So the f/4 wasn't an issue and it's a smaller, lighter lens that's just as sharp or sharper than my f/2.8.

I use Canon gear, but in the end it's no different than Nikon. While it's a great range for a lot of sports shots, sometimes 70-200mm just wasn't "long enough" (even on crop sensor cameras like yours). For a long time I supplemented the zoom with a 2nd camera fitted with a 300mm f/4 lens. Nikon offers a couple of those, too, which might be a solution for you. There's a fairly compact and much lighter weight AF-S Nikkor 300mm f/4E PF ED VR that's more expensive, as well as an AF-S Nikkor 300mm f/4D IF-ED that costs about $500 less but is larger, heavier and doesn't have image stabilization. Here's a more detailed comparison (along with the 70-200mm f/4 and 70-200mm f/2.8 for comparison): https://www.bhphotovideo.com/c/compare/Nikon_AF-S_NIKKOR_300mm_f_4D_IF-ED_Lens_vs_Nikon_AF-S_NIKKOR_300mm_f_4E_PF_ED_VR_Lens_vs_Nikon_AF-S_NIKKOR_70-200mm_f_4G_ED_VR_Lens_vs_Nikon_AF-S_NIKKOR_70-200mm_f_2.8E_FL_ED_VR_Lens/BHitems/207356-USA_1111442-REG_897230-REG_1292140-REG

An alternative that I'm using now is a single lens... in my case a 100-400mm zoom. It's certainly more versatile than a fixed 300mm focal length. For Nikon you have what may be an even better option: the excellent AF-S Nikkor 80-400mm f/4.5-5.6G ED VR. Depending upon what sports you may or may not need the focal lengths beyond 300mm. I rarely do. But for sports on large fields like baseball, soccer and football, 400mm can come in handy. Both this Nikkor and my lens are f/4.5-5.6 aperture, so up to a stop "slower" than the f/4 lenses above. So the Nikkor 80-400mm might not be great for night games unless the venue is very well lit. I keep my f/4 and even some f/2.8 lenses handy for more challenging lighting situations, indoors and night games. Nikkor 80-400mm: https://www.bhphotovideo.com/c/product/936121-REG/nikon_80_400mm_f_4_5_5_6g_ed_vr.html

I mention using two cameras with the 70-200mm and 300mm, and still do that with 100-400mm. But you might be able to get by with just a single camera thanks to the wider range of focal lengths the Nikkor 80-400mm offers. (I also usually carry a 24-70mm and need to swap to it at times.) By the way, I make a point of using two identical cameras and set them up exactly the same other than the lenses, for very quick and seamless swaps between them during fast action shooting. If you wanted to do this too, you'd need to track down a good used D7200, since Nikon discontinued that model some time ago. I see there are a lot of D7200 at fairly reasonable prices on the used market: https://www.mpb.com/en-us/product/nikon-d7200?showAll=true

I hope this helps and you upload some sample images so we can look at them and give you better feedback.

I think you are looking at the line that reads 1:4 which is not an f1.4 lens. On your crop frame camera, you are already shooting at 350mm when compared to a 35mm film camera. If indeed you have a 70-200 f2.8 or f4.0, both are regarded as very sharp lenses in the Nikon line of lenses. There is always the chance you have a bad copy which can happen with any lens with any manufacturer. As far as a sweet spot is concerned, the sharpest a lens performs is two stops from wide open. That was the standard before digital. Digital has expanded the sharpness zone and as long as you are not at the extremes of the range you should be getting reasonably good in-focus shots. On a 2.8 lens, you should be getting sharp shots between f4 and f11. Check your technique and camera settings before you claim the lens is not sharp. What ISO setting are you using? If you are set between 200 and 400 go up to 1200 ISO and try shooting at 5.6. Are you using a monopod or a tripod? Shooting at the extreme of 350mm (which is what you are shooting at the 200 setting), a slight movement at the camera position will create a lot of movement 50 to 100 ft. away.