Upgrading Drupal

I have some Drupal 6 sites which I need to move to Drupal 8 in the hope of getting them functional again.  Can I migrate them directly to Drupal 8 or do I need to do a two step migration through Drupal 7 as an intermediary?

Last time I had problems updating to 8.8.3 with composer,
so I followed this link and updated successfully to 8.8.0-alpha1:
https://www.previousnext.com.au/blog/updating-drupal-880-beta-composer.
At the moment, I want update to 8.9.2, as recommended in my 'available updates report', so please advise me how to do it correctly?

I have a D6 site which used tablemanager, a now unmaintained contrib module to present tabular data.  This was very simple data in which a large spreadsheet was processed into about 20 pivot tables to analyze various aspects of the data.  Each of these pivot tables was then uploaded and combined with some text to make a node.  I have been looking for an alternative module and most of the suggestions thus far (contentimport, tablefield, tabular) are not very attractive for one reason or another (much more complicated, no D8 version, not secure, etc.).  So, one of the interesting suggestions

Folks,

I have been using Drupal for many years but I don't count myself as an expert.  My site is very simple and uses the Bartik theme.

I recently (last week) did a core update following the recent security advisory - now using 7.72 - and very oddly I find that my default theme presents perfectly when I am logged in but to a casual visitor the theme is not presented at all - so all that is presented is bare text (although my picture _is_ displayed.

Any thoughts on what might have happened?  I have performed countless such upgrades in the past without problems.

Please ignore, this has been solved. This was related to the Content Audit and Statistics modules. Disabling them has corrected the behavior.

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I have an annoying problem with a Drupal 7 site which was recently updated from 7.69 to 7.72. The upgrade appeared to go without issue and the site was used for a couple of weeks before the problem appeared, but uid 1 cannot view the web site with the exception of the administration pages. Anonymous users and all other authenticated users are unaffected, which is why the problem was initially missed.

Is it possible for upgrading from Drupal 8.7.14 to directly Drupal 9.x, instead of upgrading it to 8.8.x or 8.9.x?