I guarantee you if i had a large reef it would be made immune to both of these invaders day 1. for a small reef its still immune to both of these forever due to the degree of access i have to the water column and all areas. a large tank is hard to clean out, you have to be more preventative.
The way i would certainly gain the permanent upper hand in a large tank is by grossly oversizing a uv unit meant for a pond that is orders too large for the tank Id have it on.
This method has been featured, before and after pic'd, and tested on our large cure threads they are easy to find. I recommend it out of practice, not guessing.
Large tanks have to use cheats that are mechanical or chemical more often than not to deal with tough invasions, this above is likely a mix of obligate hitchhikers which you can kill by direct action (dino component of that complex above) and ubiquitous ones that will always be present and react to phosphate, which by the way is ok here (cyano component)
i realize its hotly debated online whether uv is effective and against what, but im saying for the details i wrote, and this specific invader group, id beat it easily. i can name five other infestations id rather have vs this one above, oversized uv is that effective. all you do is manually remove the offender every single day (the price of early inaction=couple weeks extra work for us) and make zero biomass of it in the tank. that alone cures it from killing your anemone.
the grossly oversized uv simply handles the floaters you create in manually removing 100% of it.