GameSpot has put together a load times comparison for some BC games

Red Dead Redemption 2
- XSX: 1m4s
- PS5: 1m5s

FFXV
- XSX: 48s
- PS5: 1m10s

Destiny 2
- XSX: 42s
- PS5: 57s

MH World
- XSX: 35s
- PS5: 51s

Arkham Knight
- XSX: 58s
- PS5: 1m7s

https://twitter.com/nibellion/status/1324712038602543105
https://twitter.com/5chan_nel (5ch newer account)