Thanks a lot :) I still have some questions though.
1. Les bonnes vertus débouchent toujours sur les meilleures choses dans la vie… mais nul ne nierait que le chemin est parfois rocailleux. Why do we use nierait in conditionnel form here? And does adding expletive ne make the sentence redundant/unnatural here?
2. Parmi elles, je m’aperçois que l’intégrité est la plus difficile à instaurer. Since I want to say 'the most difficult to build/establish', can I stick to instaurer? To the best of my knowledge, faire preuve means something like 'to show'.
3. Yeah, I don't know how to translate 'consistency'. Like there are too many possible translations: constance, cohérence, constant, etc. Which one is actually the most natural?
4. Dissiper toutes les difficultés -> something like 'to tackle problems'..
5. This is more of a general question. I have a habit of building vocabulary from reading newspapers. I stumbled upon things like 'sans ambages' there. My question is, do French newspaper have the tendency to use 'old-fashioned' vocabulary?

Okay, I'll try to reply as best as I can to your questions:
1. I'd use conditionnel because no one is actually thinking about this right now. This is a hypothetical, and if you asked people, well certainly that's what they would reply but that's not what you're actually doing so you can't just use "normal" present tense. And yeah if you keep the "ne" it actually means the opposite of what you're trying to say because it would be a "double-négation". Instead of meaning "nobody denies that" it means "nobody wouldn't deny that". People would probably still understand, but you should avoid phrasing your sentences that way.
2. You can't really "instaurer" a moral value, it's afaik generally used for important institutions. Ex: L'Instauration de la Cinquième République. There are sentences you can't easily translate from one language to another, and this is one of them. "Etablir" sounds more natural/native though, and it's the literal translation of establish.
3. Thinking about it now, this is a problem I've been having for a long time. We don't actually have a word that means the exact same thing as "consistency", if we had to convey what it means we'd phrase the sentence in an entirely different way. "Constance" probably comes closest though, even though it's old fashioned.
4. "faire face à vos difficultés" then
5. It depends on what newspapers you're reading. I'm guessing it's not CNews (lol), but generally the more it's obscure/far from the "average person's" political views the more it'll tend to use words that people never use irl. For example, Le Monde Diplomatique (an anticapitalist, weekly newspaper) uses more unusual words than say "Nice-Matin" or "Le Monde". But one of the reasons for that may be that since Le Monde is published every day, it can't dive that deep in a given subject - it generally has more information, explored in less depth, than Le Monde Diplomatique (which was at some point related but not anymore), which is more analytical. I think that's a general trend that carries across newspapers, based on how frequently they're published. If you're part of the minority that reads physical weekly newspapers, you're either old (thus know the words used) or care enough about it to look up words you don't understand, which allows journalists to be slightly more poetic than they would be able to allow themselves to be otherwise.
Tell me if you have any more questions :)

Merci beaucoup, the confusion has finally been cleared up. Your insight about French newspapers is intriguing, never thought about it before. I usually read Le Parisien and L'actualité anyway. What do you think of them?

Not from Paris nor from Quebec so I hadn’t read anything from those papers recently (in fact I didn’t even know the latter existed) but I’ve checked them out and they both look like valuable resources to learn French, with varied and easy to read content. I feared that L’actualité would use slightly different vocabulary compared to French newspapers, as I’ve had that problem myself learning Spanish through reading Latin-American papers, but that doesn’t seem to be the case. Always happy to help :)