I had the same issue.
It was a conflict with Mollie Payments for WooCommerce.
7.0 Fatal Error
7.0.1 Fatal Error
7.0.2 Fatal Error
7.0.3 Fatal Error
7.0.4 No BPost Shipping at checkout
7.1 No BPost Shipping at checkout
I had to downgrade to 6.7 version.
WordPress and plugins are up to date (WC 6.5.1 // WP 5.9.3)