Upvote:0
I believe it would be best for you to get your visa cancelled (from the Hungarian Embassy) as you don't intend to use it for your "supposed" trip dates. Unused Visa may not be looked upon kindly (as mentioned by Ankur).
It is recommended you apply for the Schengen visa from the correct Schengen Country embassy to which you are actually going to travel with right travel dates and not just a Schengen country which you think has a loophole in your case. Also why not get your UAE residence permit renewed 3-4 months in advance of its expiry? I know in KSA, they allow it to be renewed in advance of 3-4 months validity starting from the date of current expiry.
However, don't think there should be a problem if you apply for another Schengen visa with travel dates after the expiry of your current valid Schengen visa. So you apply to German embassy for Schengen visa for travel dates say in November (as long as you can justify that).
Upvote:4
You should not wait nor apply for a new visa while you have a valid one.
You are allowed to have only one valid Schengen visa at any given time even if they are from different EU countries. The proper solution for your case is simple, Cancel your current Schengen visa in the Hungarian embassy and apply for a new one. Cancellation is simple and they will stamp the visa with a special stamp (you do not have to worry, it is not stamp type that will cause any kind of trouble). Once cancelled you can apply for another Schengen visa with no problems.