Hi! I feel like they don't explain this super well but the "object" sort of receives the action of the verb. Tourists can explore what? cultural sites. Chefs create what? Dishes. I was always taught to ask what or whom of the verb in order to identify the direct object. Taught what? To ask. You might get a better understanding of direct objects if you do some outside research. https://www.grammarly.com/blog/direct-object/

I am not a shill for grammarly that was just the first comprehensive article I found explaining direct objects. (am what? a shill).

I could be wrong but "to sabotage" appears to be an infinitive verbal phrase (a verb that is functioning as a noun in this case). for example "To sabotage is my favorite activity" in this example "to sabotage" would be the main subject.

I agree partially. IMO "the" is a modifier of "attempts" but "will backfire" is an example of a main verb (backfire) and an auxiliary verb (will). auxiliary verbs are also sometimes called "helping verbs." I would have thought the "kernel" would be "attempts will backfire"

Attempts is one of those tricky words that can be a noun or a verb. One of the many reasons english is such a difficult language to learn. figuring out how to break down and identify sentence clauses is not an easy subject. Don't get discouraged!

you aren't this is an extremely barebones explanation of an extremely complex and nuanced topic. This is why people hate grammar. Is there something specific you aren't grasping?