Current versions do not work with drupal 9.1.0

Problem/Motivation

Upon upgrading from drupal 9.0.0 to drupal 9.1.0, all amp pages on my website stopped working.
Whenever I try to access any amp page, I get the following "The website encountered an unexpected error. Please try again later".

And here is error message from dblog:

Error: Call to a member function getActiveTheme() on null в Drupal\Core\Render\MainContent\HtmlRenderer->prepare() (строка 279 из /web/core/lib/Drupal/Core/Render/MainContent/HtmlRenderer.php)

#0 /web/modules/contrib/amp/src/Render/AmpHtmlRenderer.php(81): Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\CurrentRouteMatch))
#1 /web/core/lib/Drupal/Core/EventSubscriber/MainContentViewSubscriber.php(90): Drupal\amp\Render\AmpHtmlRenderer->renderResponse(Array, Object(Symfony\Component\HttpFoundation\Request), Object(Drupal\Core\Routing\CurrentRouteMatch))
#2 [internal function]: Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object(Symfony\Component\HttpKernel\Event\ViewEvent), 'kernel.view', Object(Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher))
#3 /web/core/lib/Drupal/Component/EventDispatcher/ContainerAwareEventDispatcher.php(142): call_user_func(Array, Object(Symfony\Component\HttpKernel\Event\ViewEvent), 'kernel.view', Object(Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher))
#4 /vendor/symfony/http-kernel/HttpKernel.php(163): Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch(Object(Symfony\Component\HttpKernel\Event\ViewEvent), 'kernel.view')
#5 /vendor/symfony/http-kernel/HttpKernel.php(80): Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object(Symfony\Component\HttpFoundation\Request), 1)
#6 /web/core/lib/Drupal/Core/StackMiddleware/Session.php(57): Symfony\Component\HttpKernel\HttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#7 /web/core/lib/Drupal/Core/StackMiddleware/KernelPreHandle.php(47): Drupal\Core\StackMiddleware\Session->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#8 /web/core/modules/page_cache/src/StackMiddleware/PageCache.php(191): Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#9 /web/core/modules/page_cache/src/StackMiddleware/PageCache.php(128): Drupal\page_cache\StackMiddleware\PageCache->fetch(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#10 /web/core/modules/page_cache/src/StackMiddleware/PageCache.php(82): Drupal\page_cache\StackMiddleware\PageCache->lookup(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#11 /web/core/lib/Drupal/Core/StackMiddleware/ReverseProxyMiddleware.php(47): Drupal\page_cache\StackMiddleware\PageCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#12 /web/core/lib/Drupal/Core/StackMiddleware/NegotiationMiddleware.php(52): Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#13 /vendor/stack/builder/src/Stack/StackedHttpKernel.php(23): Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#14 /web/core/lib/Drupal/Core/DrupalKernel.php(706): Stack\StackedHttpKernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#15 /web/index.php(19): Drupal\Core\DrupalKernel->handle(Object(Symfony\Component\HttpFoundation\Request))
#16 {main}

Of course, tried to clear cache and upgrade to dev (version dev-3.x 87c4f57), but no luck.

Steps to reproduce

Upgrade Drupal to 9.1.0 while having amp-3.5.0 or amp-dev-3.x installed.

Other thoughts

Probably it has something to do with the masterminds/html5 upgrade from 2.7.0 to 2.7.4.
Drupal 9.1.0 requires masterminds/html5-2.7.4. Downgrading to 2.7.0 is not possible with Drupal 9.1.0.