Unable to access Drupal /admin/modules or /admin/people after upgrading to 9.2.15 -> 9.3.15

Question

Like the title says, everything was working as expected until I upgraded from 9.2.15 to 9.3.15 which was a composer based installation.

When I try to access one of the paths, the first path gives me this

The website encountered an unexpected error. Please try again later.

SymfonyComponentRoutingExceptionRouteNotFoundException: Route "user.admin_permissions.module" does not exist. In DrupalCoreRoutingRouteProvider->getRouteByName() (line 206 of core/lib/Drupal/Core/Routing/RouteProvider.php).

People options gave me this:

The website encountered an unexpected error. Please try again later.

SymfonyComponentRoutingExceptionRouteNotFoundException: Route "user.role.settings" does not exist. in DrupalCoreRoutingRouteProvider->getRouteByName() (line 206 of core/lib/Drupal/Core/Routing/RouteProvider.php).

No errors from composer, no errors in any logs, although this appears in my access.log

- [06/Jun/2022:15:06:56 +0000] "GET /admin/people/permissions HTTP/1.0" 500 3053 "https://d9d.text-based.net/admin/people/permissions/administrator" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:99.0) Gecko/20100101 Firefox/99.0"

Here is the complete error shown on the page:

The website encountered an unexpected error. Please try again later.

SymfonyComponentRoutingExceptionRouteNotFoundException: Route "user.role.settings" does not exist. in DrupalCoreRoutingRouteProvider->getRouteByName() (line 206 of core/lib/Drupal/Core/Routing/RouteProvider.php).

DrupalCoreMenuLocalTaskDefault->getRouteParameters() (Line: 310)
DrupalCoreMenuLocalTaskManager->getTasksBuild() (Line: 358)
DrupalCoreMenuLocalTaskManager->getLocalTasks() (Line: 95)
DrupalCoreMenuPluginBlockLocalTasksBlock->build() (Line: 171)
DrupalblockBlockViewBuilder::preRender()
call_user_func_array() (Line: 101)
DrupalCoreRenderRenderer->doTrustedCallback() (Line: 772)
DrupalCoreRenderRenderer->doCallback() (Line: 363)
DrupalCoreRenderRenderer->doRender() (Line: 435)
DrupalCoreRenderRenderer->doRender() (Line: 201)
DrupalCoreRenderRenderer->render() (Line: 463)
DrupalCoreTemplateTwigExtension->escapeFilter() (Line: 43)
__TwigTemplate_00188c1691be8aad1e9679a8355ec8b1aad8fb0e1a0552901f64354cc31fc535->doDisplay() (Line: 405)
TwigTemplate->displayWithErrorHandling() (Line: 378)
TwigTemplate->display() (Line: 390)
TwigTemplate->render() (Line: 55)
twig_render_template() (Line: 384)
DrupalCoreThemeThemeManager->render() (Line: 422)
DrupalCoreRenderRenderer->doRender() (Line: 201)
DrupalCoreRenderRenderer->render() (Line: 463)
DrupalCoreTemplateTwigExtension->escapeFilter() (Line: 86)
__TwigTemplate_52bf370994174cae6411a160df9bc52e747d5a7e02be204f64e1e34dad454a33->doDisplay() (Line: 405)
TwigTemplate->displayWithErrorHandling() (Line: 378)
TwigTemplate->display() (Line: 390)
TwigTemplate->render() (Line: 55)
twig_render_template() (Line: 384)
DrupalCoreThemeThemeManager->render() (Line: 422)
DrupalCoreRenderRenderer->doRender() (Line: 201)
DrupalCoreRenderRenderer->render() (Line: 162)
DrupalCoreRenderMainContentHtmlRenderer->DrupalCoreRenderMainContent{closure}() (Line: 564)
DrupalCoreRenderRenderer->executeInRenderContext() (Line: 163)
DrupalCoreRenderMainContentHtmlRenderer->renderResponse() (Line: 90)
DrupalCoreEventSubscriberMainContentViewSubscriber->onViewRenderArray()
call_user_func() (Line: 142)
DrupalComponentEventDispatcherContainerAwareEventDispatcher->dispatch() (Line: 163)
SymfonyComponentHttpKernelHttpKernel->handleRaw() (Line: 80)
SymfonyComponentHttpKernelHttpKernel->handle() (Line: 58)
DrupalCoreStackMiddlewareSession->handle() (Line: 48)
DrupalCoreStackMiddlewareKernelPreHandle->handle() (Line: 48)
DrupalCoreStackMiddlewareReverseProxyMiddleware->handle() (Line: 51)
DrupalCoreStackMiddlewareNegotiationMiddleware->handle() (Line: 23)
StackStackedHttpKernel->handle() (Line: 708)
DrupalCoreDrupalKernel->handle() (Line: 19)

Composer shows no errors when updating, I also updated the database via drush. There are no errors in any logs either.

Answer 1

Not 100% sure what fixed it, but I restored from backup and rebooted from 8.9.18 and cleaned my modules folder. Some modules were installed via drupal UI, only in my modules folder, not in module/contrib, so I uninstalled those modules and deleted them from the modules folder, then reinstalled and enabled them via Composer . After that I cleaned the cache and performed a drush updb and then continued upgrading to 9 as before. Then it worked.