hi @cyb3rx welcome to the community 
maybe migration using intermediate Docker installation would be easier… you don’t need a full-blown installation just the core. the advantage would be - each Docker image ships the right php, Apache and configs… upgrading is pretty simple and you can later migrate to you final destination system running whatever architecture you need. The system doesn’t need to be really performant as long you can afford the downtime…
Docker community image
Docker upgrade procedure
Docker persistent data
if you decide to use docker later here is a more advanced setup:
docker-compose-setup-with-notify-push-2024
Nextcloud docker compose setup with Caddy (2024)