Reds take time to grow actually red without CO2 in sme cases. Meaning the plants
get red/more red with maturity. I use Excel at 2x recommended doses and a couple
of my red(type) plants are just green so far. But the base of them is red but the new growth that is while they are in my tank is just green. I do have an Alternathera reineckii that so far has stayed red. The new growth is the same color as the rest of the plant which was grown elsewhere before I got it. Might be a good one for you
to try due to what seems to me to be easier to keep red growth than Ludwigia Repens.
Any reds are going to be needing to be out in the open with no shade to stay red.
Looks good so far/nice placement of the rocks.