Your requirements could not be resolved to an installable set of packages.
Problem 1
- sulu/sulu[2.6.0, ..., 2.6.3] require symfony/http-kernel ^5.4 || ^6.0 -> found symfony/http-kernel[v5.4.0, ..., v5.4.41, v6.0.0, ..., v6.4.9] but it conflicts with your root composer.json require (^7.1).
- Root composer.json requires sulu/sulu ^2.6 -> satisfiable by sulu/sulu[2.6.0, 2.6.1, 2.6.2, 2.6.3].