Seeking Pruning Technique

My plants have been growing good but I'm having trouble finding info on how to prune most of the plants. Of course, there are the videos of people "scaping" on a time lapses. Or youtuber showing how to make more stem plants bushier.

Here are some questions I have:

What should I do you when my stem plants are growing too tall and the base of the plant is getting too bare? Should we chop off the bottom and replanting to top?

How about when my Echinodorus Ruben is outgrowing the rest of the plants in the aquarium, should cut off the leaves from the base and let the smaller shoot up or trim the big leaves to smaller one?

What should I do with plants with a Rhizomes (i.e.Cryptocoryne wendtii) or plants with short roots (i.e Jungle Vals) getting uprooted because when I'm trying to move some of my other plants around or cleaning / Syphoning the near the bottom of the tank.

90 percent of my carpet plants got dies from the begin, however, I was able to save a small bunch. Can I get a decent carpet with a small bunch of Staurogyne repens?
Also is there a way to increase its growth with my Staurogyne repens in a hi-tech tank? I might have too many taller plants surrounding

Is there a way to thin out my Alternanthera reineckii because some of the plants are growing too bushy?

Is there a how-to site or book or videos on how to scape/ prune aquatic plants?

Thanks a bunch