Okay, Select the Subjects which means to totally protect them in a Mask. If you were in Photoshop then you could do it there and bring the Halo-Like areas in by bringing the Smooth Edge into the equation to make your selections exactly where they should be. In other words, You would bring everything just to Your Floral Subjects and You could make Your Background look very consistent. You did a Good Job with Your Images, but I think that it would make Your Floral Stand out from the Background. I'am not being Hyper-Critical, I believe that You took the time to shoot and Photograph everything right, so now with a Few Minor tweaks maybe you can show the smooth and flow of Your work. Please do not be offended as I was not trying to make you feel like you failed. You succeeded, so now go the extra mile. Also, it helps when you use a Tripod with a rail system to take a number of shots from the same distance, aperture, and shutter speed. I may shoot this image to my BenQ Monitor and see if I can help You so It won't seem like I'am sitting here telling You what to do. Helicon really does help, but I have turned out some decent stacking in Photoshop 2022 as well. We have to help each other out. There are nights that I will Edit an Image and come back the next morning and wondered how an Alien took my Computer and messed everything up.

You have to remember that in order for focus stacking to blend smoothly the depth of field covering the subject of one image needs to overlap with the depth of field of the next image. As you know, the depth of field varies with aperture and distance. Your photo appears to occupy a depth of about 2 to 3 ft. At close up distances 4 images would likely not be enough to cover the depth of a single flower. Think of each image being an in focus slice of the scene. When those slices don't overlap the stacking software needs to connect/blend the images in between without having the detail. More overlap is better. I've used 50 images for a single flower. or a tiny piece of jewelry.

Landscape stacking is a whole other matter. Typically the depth of field is huge compared to close up work. 4 to 6 images may be sufficient for a landscape scene.