BS! Godfather Bomb

No they will be fine. Stop going to where you read this. It is obvious grow bro bs.

I've always topped my plants above the 5th nodes and never had any issues! I even never noticed any growth slow because of that so your plants should be fine 😎

You can top first node if you really want. Given enough time in veg they will recover. They look good.

Potassium deficiency.

I've been made aware that your grow is in Actual Dirt, and not Coco Coir, which was the basis for my suggestions. In the case of soil it's a different matter all together. If you've not mixed aeration of some soft then you will likely water log your soil and suffocate the plant and cause the roots to rot and die. All you can do is water with pH'd water.

Looking at your diary, 800 ppm is a bit low for these size of plants at this stage of the growth. Check the EC of the drain to really know what’s happening.