Speed and type of views

Hi everyone,

my queries are running somehow slow. I'm using views now because it's more convenient to get the filters sorted correctly, but it seems it has dropped my query speed vs questions. Is it possible?
Between questions, Models and views, will there be a very noticeable query speed difference? Is either of the 3 recommended?

Also, when I setup a question, I think it would make sense to restrain the number of columns queried, I can select just some columns when I prepare the question, but once it's done, it looks like all columns are included in the answer anyway... I am correct?

Depends upon the view design and the database.
Are you able to compare the SQL that Metabase is generating?

Cached models can be faster. Seems to depend on amount of data. I'm not a fan, I'd rather do the work at the database.

a view is just an abstraction of a sql, so if that SQL is slow, then everything is slow on top of it