Hi there,
Thank you for contacting WooCommerce Plugin Support. I understand you are experiencing a fatal error on your site after updating to WooCommerce 8.5.
This is a known issue that affects some sites using WooCommerce 8.5 and our developers are working to fix it as soon as possible. You can follow the progress of this issue on GitHub.
https://github.com/woocommerce/woocommerce/issues/43406
In the meantime, you can roll back to WooCommerce 8.4.0, which is a stable version that does not have this problem. To do this, you can manually download and upload WooCommerce 8.4.0 from this link. Please make sure to back up your site before doing this, as rolling back may cause some data loss or compatibility issues.
I appreciate your patience and understanding. If you have any further questions or need more assistance, please let us know.
Have a great day!