Best treatments for nail psoriasis

Hi, I have had general plaque psoriasis for most of my adult life (I'm 38 now) in places like elbows, ankles, hands then in the last 15 years I developed nail psoriasis which at times has almost cleared up only to come back with a vengeance at other times like now where I'm having to cut them back every day or two otherwise they look yellow. I have never quite worked out what has cleared it up when it does, but I do know that beer or stress seems to trigger my general psoriasis, even if it's one night of drinking every two weeks socially as I do not even drink alcohol during the week. Weirdly it seems to be worse with beers than wine, so I wonder what it is in beer that causes it. About 5 years ago I bought a small UV lamp (dermfix) which seems to clear up my skin psoriasis within a few weeks or so, it even made some stubborn bits on my palm disappear altogether however not the nail psoriasis. Probably because the UV cannot get through the nail. I also tried rubbing Dovobet on the ends but no luck either. Part of the problem is they take so long to grow back after so it's also hard to pinpoint what actually helps yet hardly any time for them to become messed up again, so frustrating. It makes me so self conscious wondering what people think when they see the state of my nails. Has anyone found anything that actually helps specifically with their nail psoriasis, or pinpointed anything that has cleared it for themselves? Or also triggers they have worked out? The normal plaque I can solve with the UV lamp but the nails I'm keen to work out. Also has anyone found anything in their diets that was a culprit too, for example I have seen that dairy or bread can be bad, but I'm not sure. I enjoy my toast and diary. Thanks in advance, Lee