Need help with hard edges

No matter the polycount increasement to 2 or 4 quads more....
If you create such multi-polygons, like on your first screenshot, you create a problem, don´t expect nice results.
No matter if hard or smooth edge, you won´t achieve a nice results.
Try to stay within quads. Or tris and than subidbide into quads with a modifier, but if you are modeling manually,
try always to connect your topo to quads and don´t allow your software to tesselate your topo with its algorithm (you see it on your screenie with the faulty smoothing). I know that if it comes to create good edges for mesh fidelity when a potential buyer could even subdivide something, if you keep it in quads, it shoudl work out. So my personal advise is try always to avoid multi-polygonal faces that create issues of all kinds.

@3DCargo: I absolutely agree with your last sentence.

Moving the edges to the base of the wall is mitigating the problem - not solving it. Using loops or quadrating the area such as what @ricomcarlos suggested will prepare the artist for future situations when working with rounded or more complex surfaces. Either way, glad to see you are trying to help @gjuroo - if all you have is a hammer, everything looks like a nail.

@3DCargo: I actually gave 3 advices... First one was to start with more geometry. Second method he actually used in solving his problem. Third method I mentioned, solves one problem but it creates another one. It was up to OP to choose the method which suits his needs.

Of course one doesn't negate the other, that's just splitting hairs. My point is that when learning modelling you are better to start with less polygons than more, else is just bad advice. It's easier to bevel/chamfer/split edges than to remove them - especially when learning toplogy.

Work how you prefer it doesn't matter if it looks correct and fits the specifications, I just don't personally agree with your advice in this situation.

The answer is never 'you need more geometry'. You need better topology. Sorry @gjuroo but I disagree with your statements.

This is what you get wit little more geometry:

https://i.imgur.com/mRwd3k6.jpg

Ok, I managed to solve this in 2 ways without increasing polycount and continuation over the wall. Here are the results:
https://imageup.ru/img97/4027894/result.jpg
As you see, wall topology remains uniform and don't produce any significant pinching. It's now moved to the bottom and I can hardly notice it there.
Thank you all for participating! It means a lot to me.

https://photos.google.com/share/AF1QipO5vxmdptEfeNGLaVjXH7XJ4uHsye95UogfPy5ynvQnuzs8GIlFIiI_LwRJ6k9LIg/photo/AF1QipNTBb21eMDAIsFrEMwbNiHBG77iknK1vcPOTMeY?key=WkU5dlNFUnFKS3E2eHVuU2J6UjM1bHV2b2luYjF3

Maybe this will work?

Loop these edges through and you can remove the pinching:

https://ibb.co/qnnqCX8

The most simple answer is that you delete this model and start a new one with more geometry from the scratch. As hard it might sounds, sometimes it's the best solution if you want to do a proper model. It happened to me many times. I started with 8-points cylinder and it all went down the drain when I started adding details. You don't have to be "cheap" with geometry. In start it might seem too much but in the end you don't have to use large subdiv number. With good start geometry, you can end up with only subdiv1 which will give you same result as subdiv3 but without pinching problems.

Have you tried to solve up-right geometry as you did on the bottom-left (three points merged to one and continued to edge that goes up)? Maybe on this bottom-left is also some shading but maybe it's not so important (and visible) for final product.

Third solution is to continue theese edges over the wall and then eyeball the geometry to get the best result. [WARNING: This is very intimidating process for persons with OCD (which we all have)].