no wp blog page or wp-admin GUI after upgrades from 6.0.1

The WordPress critical error can have a variety of causes, though the issue often can usually be traced back to an issue with PHP:
– either your memory limit being surpassed, or an error in your code, plugins, or theme. It may also be an issue of database corruption.
– Since the problem can be caused by any number of things, check the error log on your server. If you can’t find the log, please contact your host. Meantime, enable wp_debug and wp_debug_log and after an error, look at wp-content/debug.log to see if anything gets logged there.?https://www.ads-software.com/support/article/debugging-in-wordpress/
– Useful articles:
https://www.wpbeginner.com/wp-tutorials/how-to-fix-the-critical-error-in-wordpress/
https://kinsta.com/knowledgebase/there-has-been-a-critical-error-on-your-website/

Hi, thanks for help. The debug output shows the following (with replaced site names):

[07-Nov-2022 00:30:30 UTC] PHP Warning: require_once(/home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/class-wp-textdomain-registry.php): failed to open stream: No such file or directory in /home/myhostsite.com/username/mysite.com/htdocs/wp/wp-settings.php on line 155
[07-Nov-2022 00:30:30 UTC] PHP Fatal error: require_once(): Failed opening required ‘/home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/class-wp-textdomain-registry.php’ (include_path=’.:/usr/share/pear/’) in /home/myhostsite.com/username/mysite.com/htdocs/wp/wp-settings.php on line 155`

Try Manually upgrading. When all else fails, download a fresh copy of the latest.zip file for this release (top right on this page) to your computer, and use that to copy up. You may need to delete the wp-admin and wp-includes folders on your server (NOTE: do not delete the?wp-content?directory or your?wp-config.php?file)?Read the?Manual Update directions first.

BACKUP: If you haven’t already done, always backup everything (including your database) before doing any actions, just in case something really goes wrong. You can never have enough backups! See https://www.ads-software.com/support/article/wordpress-backups/

I did a manual upgrade – did not delete wp-contents folder or anything inside or upload anything into it. I also did not do a normal upgrade after this, and have not reenabled plugins or themes. My blog site has returned https://www.mysite.com/wp, but the dashboard at https://www.mysite.com/wp/wp-admin brings up a 404 error message. Below is the debug info:

[11-Nov-2022 00:12:08 UTC] PHP Notice: Function WP_Block_Type_Registry::register was called incorrectly. Block type names must contain a namespace prefix. Example: my-plugin/my-custom-block-type Please see Debugging in WordPress for more information. (This message was added in version 5.0.0.) in /home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/functions.php on line 5835
[11-Nov-2022 00:12:08 UTC] PHP Fatal error: Uncaught Error: Class ‘Requests_Cookie_Jar’ not found in /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/class-requests.php:591
Stack trace:
#0 /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/class-requests.php(365): Requests::set_defaults(‘https://www.mysite…’, Array, NULL, ‘POST’, Array)
#1 /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/class-wp-http.php(395): Requests::request(‘https://www.mysite…’, Array, NULL, ‘POST’, Array)
#2 /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/class-wp-http.php(615): WP_Http->request(‘https://www.mysite…’, Array)
#3 /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/http.php(179): WP_Http->post(‘https://www.mysite…’, Array)
#4 /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/cron.php(922): wp_remote_post(‘https://www.mysite…’, Array)
#5 /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includ in /home//home/myhostsite.com/username/mysite.com/htdocs/wp/wp-includes/class-requests.php on line 591`

My blog site has returned

Glad to know it ??

but the dashboard … brings up a 404 error message

Try manually resetting your plugins (no Dashboard access required). If that resolves the issue, reactivate each one individually until you find the cause.

If that does not resolve the issue, access your server via SFTP or FTP, or a file manager in your hosting account’s control panel, navigate to /wp-content/themes/ and rename the directory of your currently active theme. This will force the default theme to activate and hopefully rule-out a theme-specific issue (theme functions can interfere like plugins).

i hadn’t done anything more yet, but rechecked wp-admin page again today. There was a message that the database needed upgrading – click to upgrade. It upgraded instantly and the dashboard was available again.

Thanks for your help.

Glad its sorted ??