Questions about example sentences with, and the definition and usage of "Brideshead"

A: The word class of "one" does not really change in this example. It is still a pronoun, referring back to a "scene of desolation". It remains a pronoun, singular, whatever words we choose to use to follow it.

You can follow the pronoun with a direct description, as in the original : "more brutal than this." You could call this an adjective phrase, if you wanted to. This is good.

Another option is to follow the pronoun with a desriptive clause. A clause is a group of words with a verb in it. I suggested using a "that clause" - "that" followed by a verb, "would be", and then an adjective phrase. This is also good

Either way, you are simply explaining the type of scene desolation that you never expected to see.

In British English, you can often freely choose "which" or "that" for your linking word. American English has a stricter and different policy, preferring "that" for some cases and "which" for others.

I hope this helps!

https://dictionary.cambridge.org/grammar/british-grammar/adjective-phrases

https://dictionary.cambridge.org/grammar/british-grammar/that-clauses?q=Adjective+clause+

https://www.grammar-monster.com/glossary/adjective_clauses.htm