Hmmm. I think I’m hitting a similar issue. Running a now 10 year old (!) Discourse instance that’s never been migrated and has been updated consistently inconsistently 
Tried updating Docker Manager via the Dashboard today and am now getting this in browser console when trying to render the Admin settings (specifically, the Customize link generated by the “try disabling some frontend components” message):
loader.js:247 Uncaught (in promise) Error: Could not find module `discourse/lib/decorators` imported from `discourse/plugins/docker_manager/discourse/routes/update`
Getting a PUPS error when trying to rebuild on the CLI:
FAILED
--------------------
Pups::ExecError: cd /var/www/discourse && su discourse -c 'yarn config set network-timeout 60000 -g' failed with return #<Process::Status: pid 280 exit 1>
Location of failure: /usr/local/lib/ruby/gems/3.3.0/gems/pups-1.2.1/lib/pups/exec_command.rb:132:in `spawn'
exec failed with the params {"cd"=>"$home", "hook"=>"yarn", "cmd"=>["if [ \"$version\" != \"tests-passed\" ]; then\n rm -rf app/assets/javascripts/node_modules\nfi", "su discourse -c 'yarn config set network-timeout 60000 -g'", "su discourse -c 'yarn install --frozen-lockfile && yarn cache clean'"]}
bootstrap failed with exit code 1
** FAILED TO BOOTSTRAP ** please scroll up and look for earlier error messages, there may be more than one.
There are no other apparent errors in the bootstrap. This is a single-container install… any ideas for how I get unstuck? The site is currently still up but in a pretty bad state.