I usually do 76-82F, Amazonian fish can go higher.
Higher temps usually means the tank needs to be better managed with higher quality food (higher quality food means lower waste) and more water changes (no slacking off).
Goldfish are fine in tropical temps. They have been introduced and become established in all the exact same ecosystems we get all of our tropical fish from (Tropical SE Asia, Africa, Middle East, and Amazonia). Effectively all are bred on tropical fish farms and are actually stressed by my fellow Americans taking them from that to their room temp tanks in homes with AC.