Ipads have been oled for years now. The samsung galaxy s has literally had an oled for 16 years now. If these screens aged badly, don't you think Apple/Samsung either would've switched away or built more burn-in resistant oleds?

Also brightness degradation on especially a tandem oled is unlikely within its reasonable lifespan. Tandem oleds are the literal peak of display technology for this size of panel. Image quality wise, there's no downside.