Need help!

Hey everyone I'm very new to the planted aquarium community and could use some help!. I've tried my hand at some plants that browned out and died within a month or so. These plants were just simple java fern and Anuinbus. I have a few theories but am unsure on what caused this. I know I set myself up to fail from the beginning and I am interested in suggestions on what I can do diffrently to help my tank succeed.

Here is what I have and what I was doing. -125 g 6 ft long tank 24 inches deep.I have african cichlids tropheus, peacocks and haps. They did not seem to bother either plant. I have 9 baby bristle nose plecos added after the plants were almost dead. I am willing to take them out if they'll cause a problem. ( I have 4 other tanks) I have lime stone in my tank and my ph is 7.8 my temp is 82. I was feeding the plants flourish nutrients for plants regularly. I have pool filter sand as my substrate. i also tried to attach one of the java ferns to a rock. I did not bury anything except the roots on the Anuinbus. For lighting i have 3-24 inch led strip lights. I will include the specs on them below.

If any one could help me out and let me know what I did wrong. I know my ph is up there but it should be OK fir the beginner plants I think. My fish do not seem to bother the plants. I feel my lighting is poor could that be my main problem? I appreciate any help Thanks you!

Beam works led light
Dimensions - 23.00” x 5.00” x 1.00”
Brackets add 0.65" in height
Includes 78 LEDs
400 Lumen
Super energy efficient .06 watt LEDs
72x 6500K LEDs
6x Actinic 460nm LEDs
Uses 7 watts
Slim and contemporary light design
2 mode on / off function for day and night use
Mode 1 turns on all LEDs
Mode 2 turns on 6 LEDs
Extendable bracket - 24"-30" (60 cm - 75 cm) max extend
Splash guard
110V - 220V