What kind of paphs other than strap leaf (is it multi-flowering type or complex?) I don't grow species and large multi-flowering ones.
So other than this, I can probably help with the culture because I do quite good with paphs and have quite a few of them.
What do you grow yours in? What kind of care do you give to them?
What do they look like when you say they are on the decline?
I have paph. Armeni White, which is a hybrid so probably a lot easier than either of its parent, but I haven't tried species so cannot really say for sure.
I did hear that armeniacum can be pretty tough.
Delenatii...one thing I know is that they need extra water while growing and cool&slightly drier weather while resting.
Strap leafed ones- If they are multi-flowering, they need a lot of light and they are epiphytes, so use different mix other than conventional paph mix.
That's about all I know.
If your strap leafed ones are complex paphs, then you can grow them as other hybrids but green/yellow colors need cooling to flower well.
These can be quite slow growing, but once they form multiple fans, they can bloom every year I think. I have one that blooms every other year.
almost threw it away when it skipped flowering. now I know better!
Again, let me know what your paphs look like and how you care for them, so I can better help.