I have a fiddle leaf Bush and it looks quite bulky at the bottom. I want to trim it and propagate what I can remove.

Should I (can I?) separate into 4 plants since there are 4 separate stems? I've tried to separate them lightly but was too scared to injure the plant!

Or should I cut off the stems and propagate?

Not sure I understand your goal well enough. What do you want your plant to look like? Most people are trying to get their plants to look more like yours, full of leaves from bottom to top.

I agree with Tiffany. I think your Plant looks fine. However, aesthetics are a very personal matter.

You could cut off some of the lower leaves that you feel make it look too crowded. That would have no effect on the plant's health.

Likewise, you cut could off more or more stems at the base without harming the remainder of the plant. Just remember that what you remove can't later be undone.

Perhaps you have seen specimen Ficus lyratas that have a single main stem with several branches and lots of foliage only at the top and that is what you are trying to achieve. That is very hard to do. Greenhouse growers start the process very early using thicker stem cuttings to start with and keeping the plant pruned throughout its growing process. Even if you were to remove all but one trunk, it will never develop into the thick-trunked specimen Fig trees that you may have seen.

Your Fiddle Leaf Fig (Ficus lyrata) looks beautiful, happy and healthy to me and I wouldn't change a thing! I'm not really sure if I understand what you mean by the plant looking "bulky" at the bottom. Do you not care for the look of lower leaves and prefer bare stems, with only leaves at the top of the stems? I've seen Fiddle Leaf Figs planted in ground here in Florida with well formed trunks but many times when they are greenhouse or nursery grown for sale as houseplants, there can be two, three or even four separate stems rooting together in the same container to create a fuller look. As the stems get taller, lower leaves will sometimes naturally die and fall off, leaving bare stems. If your container has more than one plant, you could unpot it and gently separate the roots (that have more than likely entwined together) and repot each into separate containers but many, thin roots may be damaged when doing so. If the height of your Fig is an issue, the tops of the stems can be pruned; remove the lower leaves and pot them in small pots for additional plants.

My impression was that this pot has 4 separate plants. If that is what you are dealing with, the grower probably stuck 4 cuttings to make it look fuller sooner. Like Lin says, you can very carefully divide the plants but with the roots entwined it will not be simple and you could possibly lose all 4 plants. Like the others, my thought is to just leave it as is.