I'm facing a weird permission issue with an old backup, not sure what the issue is or how to debug this kind of issue with ddev

The site was built with drupal 7 and ran with php 7.2 back in the day,

Warning: mkdir(): Permission denied in DrupalFileCache->check_filecache_directory() (line 128 of /var/www/html/melodicpixels.eu/sites/default/modules/filecache/filecache.inc). 

Selinux is set in permissive mode and i'm the owner of that path. The site does load but that warning is puzzling me

I've managed to get a backup of the site working with ddev, imported the database etc and that's working well, but i can't figure out to give another ddev setup access to said database, surely this can be done?

As the subject says, I'd love to edit some theming colors to recreate an old site stuck at Drupal 7, the theme itself is Bootstrap Business and while this was part of the theme back in the day those options no longer exist in the current version for D11

What is the best/recommended way in 2026?