I likely should not post as I can not help, but, had to say that I had pretty much the same results. I have had a fish only tank for about ten years and tried plants four times each time a failure and each successor attempt with changes I thought would improve results. My last attempt ended about 2 months ago when I was faced with growing a tank full of algae and dying plants each three days and spending 3-4 hours cleaning things up.
I added a CO2 system and PPM fert program last time which together with the plants not growing made a wonderful environment for the algae.
I have since learned that I had too much light, I did not take sufficient care in planting my plants, and I had questionable substrate.
I have changed the substrate now. Changed my light now so that I have low/med light at the correct color, and am prepared to plant using more care next time.
I am going to try low tech this time and not use my CO2 or PPM fert program and see what I get. I am letting my tank stabilize after the new substrate and will order plants in another week.