How much have you sampled in niche? Places like luckyscent.com, where you can order niche samples, are really useful here.
When you say opulent, not-too-vanillic, my mind goes to $$$ Amouage: Ubar, Gold (man and woman), Epic, and more. Or $$ Chanel Bois des Isles. But very cheap Stetson Original (for men, that is) could work at times; it's a bright floral oriental.
Fresh summery is more complicated because most fresh stuff is rather sharp and chemical. Citruses, which are fresh and pleasant, simply cannot last, it's a physical fact. You can explore vetivers, usually marketed to men. Again, $$ Sycomore by Chanel. Or even Tom Ford Grey Vetiver.