What probably happened to your plants is more than likely the absence of an actual "Plant" light. I tried many a plants over the years and all the time the just slowly died off. With my new tank I got a specific "Plant" light a Finnex 24/7 planted plus led light.
This is what I started with.
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And now some months later
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I did get alot of growth during the summer when I had some real sunlight helping out but now it's winter in the PNW, where there is no such thing as sunlight till spring comes back around. The Finnex is keeping it all alive and still growing.