I need 35 and 25-foot cables for my two different 4K displays. I use Monoprice 'active' cables for both and have not had any issues whatsoever. I see the last one I bought is not in stock. It may have been replaced with 8K? https://www.monoprice.com/product?p_id=14131

They are directional and marked to remind you that one end is the source and the other is the display.