Better to keep reporting the spam using the tools gmail provides, eventually they'll be able to filter most of it out for you, but you have to report it to them as spam.
Better, because you can't change the email address of your gmail account, and you can't change the gmail account linked to your channel. You're stuck with it (for the most part).
If you were willing to give up that gmail address and use a NON-gmail address, you could go to the Google account, add a NON-gmail address as a secondary address, then use the form Google provides to choose to remove gmail from that Google account (NOT "close" the gmail account, you would remove gmail "as a service" from that Google account). The Google account, still permanently linked to your channel, would use the secondary non-gmail address from then on.