How far was the Metternich system able to control the rise of liberal and nationalist ideas in the German states from 1815-48?

The Metternich system was able to greatly control the rise of liberal and nationalist ideas in the German states, as is evidenced by the Carlsbad Decrees, which severely limited that spread of such revolutionary ideas, the Congress of Troppau, which resulted in an alliance between Austria, Prussia and Russia to suppress revolutionary activity which made it virtually impossible for a revolution to break out since the nationalists and liberals were not strong enough to win against this powerful alliance and the use of a police state and spies held at Metternich's fingertips, which allowed him to gain valuable knowledge aiding him in his quest to diminish nationalist and liberal feelings in the German Confederation. Though historians argue that the Hambach festival, uprisings in south of Germany and the formation of a Young Germany community showcased the cracks in the Metternich system. However, the system persisted nevertheless and came out victorious in the end as the organisers of the festival were prosecuted, and Metternich responded with his own display of strength by releasing the 6 Articles and then subsequently, the 10 Articles which limited if not finished the potential for liberals and nationalists to uprise.
Metternich secured the agreement of the main German states in August 1819 for the repressive Carlsbad decrees. These had three key features; each university was to have an 'extraordinary commissioner’ assigned to it, to supervise the teaching programme ensuring that no liberal or nationalist theories were being taught. Liberal professors who undermined the established order were to be removed from their posts. The member states of the Confederation, and the Diet, were to censor the newspaper press. Having no access to speak one’s mind in the press limited
the scope of the nationalists and liberals to spread their ideology. A central investigating commission was to be set up in Mainz to root out organisations promoting liberal and nationalist ideas, which meant that it was nearly impossible to recruit people for the nationalist and liberal cause, since people would not be willing to potentially put their lives at risk for this movement that was already limited in numbers to begin with and didn’t show any potential of reaping rewards anytime soon.
Metternich supported the idea of European Congresses which included meetings with the Great Powers of Europe to discuss and settle international disagreements and maintain peace. At the
Congress of Troppau in 1820 discussion centred on revolutions which had broken out in Spain, Portugal, Piedmont and Naples. Tsar Alexander I of Russia, who agreed with Metternich’s
reactionary beliefs, presented a proposal that Russia, Austria…