If there is no FPM available and an installed HTTPS certificate, Symfony server will proxy requests to the built-in PHP development server. It will lead to an infinite loop of redirects if HTTPS is required. The reason is assert(empty($_SERVER['HTTPS'])).

The simples workaround is to add a line into public/index.php:

$_SERVER['HTTPS'] = 'on';

Another solution is to use FPM. Unfortunately, the VSCode devcontainers does not provide FPM out-of-the-box (see microsoft/vscode-dev-containers#1296)