A lot of what follows is very much personal taste Andy, so please take this as "For What It's Worth". Your tastes very probably vary; I know for a fact that many people's tastes do compared to mine! And that's fine by me.
So, FWIW, I do like the overall "shapes" of the compositions in #1, #2 and #4, but for my taste the use of a large aperture of f/2.8 for all of these only really works for the second image. So little is in focus in the first one that my overall
impression is of an image that is out of focus. Actually, I can see that the some of the left hand pink flower and some of the stem to its right, and a very small part of the opening flower in front of it is in focus, but that isn't enough to make the image cohere, for my eyes, especially since the non-sharp ? sepals of the opening flower cut across and block off part of the flower whose stamen is in focus. In the last image there are two flowers in focus, but again my is drawn away from them by the out of focus buds and flower below and to the left of them. In the third image, also on the left there is an out of focus bud obscuring the centre of a flower that looks like it may be in in focus from the tiny part of it that is visible. And on the right in the third image there is an in focus bud on the left that is cut off by the edge of the frame, which sits uneasily to my eye.
So these comments have to do with a combination of dof and composition. FWIW I use various apertures for close-ups of flowers, down to and including f/32. I never use f/2.8, because I don't have it available, so the smallest aperture I use is f/4 to f/5.6, depending on focal length (and yes, I use a zoom lens not a prime), and I don't often use that small an aperture. I'm more often around f/8 to f/13 or so. Even with f/32, depending on the configuration of the subject and the background, the background may be thrown quite a long way out of focus.
In general, as a rule of thumb, I try (it's not always possible of course) to not to have an out of focus element of the subject that
appears to be nearer to the camera than the parts of the subject that are in focus. Where that isn't possible, I prefer to make the nearer-looking out of focus elements as unobtrusive as I can make them.
A last thing on the composition front, I would at least get rid of the tiny nib at the bottom of the third image to the left of the stems, and I would probably have cropped the bottom of the image to remove the downward pointing bud that is truncated by the bottom edge of the image.
The white balance looks very different between the first two images. The first one looks rather cold (blue) to me, as indeed do #3 and #4. I much prefer the colours in #2, which is all round my favourite image of this set. As to whether the colours are true to life of course I have no idea. To be honest, as long as the colours in an image don't look positively impossible/silly/overcooked or whatever, that is, as long as the look broadly credible (as in "they might have looked like that"), then I'm not really bothered if they actually looked like that on the day.
Do you use a grey card when shooting in natural light? I have found this make a huge difference to colour renditions. I don't always use the grey card value, although I often do, but even if I don't it usually provides a pretty good starting point. And in some cases it makes sense of colours that I simply can't get to look right and/or nice by playing around with the sliders. (btw, do you shoot RAW or JPEG? Grey card works fine for JPEG as well as RAW, but it seems to me that, at least in Lightroom and I suspect with other software too, it is possible to make much finer adjustments to white balance manually if working with a RAW image.)
I hope there is something useful or at least something worth thinking about in all this, even if our tastes (e.g. about dof) are rather different.