"I eat expensive meat."
Anywhere there's sound there should be the option of text too. For accessibility, even for those of us that just want to turn it off now-and-then or are in noisy places. When the sound craps out they could have backup options. Ironically that is one area in which the Japanese are ahead of us.
No, it would not be correct since you can't replace を with お. All of the kanji in the sentence are learned in the second grade, so it'd be weird to see the sentence without all the kanji I think. 高い肉を食べます would be the best way to say it. It would be clear from context that you are describing the person you are speaking/writing to.
Not 100% of the time, no. Sometimes, for example, your adjective and your subject will also need a connection. In the case of i-adjectives, like 高い here, you can just directly attach them to the front of the noun, but there are certain other adjectives, called na-adjectives, where you need a な between the adjective and the noun.
For example, if you wanted to say, "I eat special meat," it would be 特別なにくを食べます。(特別 = とくべつ = "special")
Sometimes the adjective can go at the end of the sentence, too. For example, the sentence, "Meat is delicious." would be にくはおいしいです。(おいしい = delicious)
You would first have to nominalize the verb by using the dictionary form and adding の or こと, then mark it as the subject with が (or topic with は) and end it with your adjective (or an optional です to make it more polite)
肉を食べるの or 肉を食べること - "eating meat" (noun) (no and koto are pretty interchangeable
を is the direct object particle, used for all direct objects of transitive verbs no matter their size or state.
Putting a が after meat would make it sound like the meat is doing the action "Expensive meat eats"
Perhaps you're thinking of 個 ko, the counter most commonly used for small round objects?
"Expensive meat" has the adjective "expensive" directly modifying the noun "meat"
高い肉 "expensive meat"
肉は高い「です」would be "Meat is expensive"
肉を高い食べます is like "I eat meat expensive" or "expensive I eat meat" which doesn't really make sense.
Counters act like adverbs and can be placed anywhere before the verb in a sentence, but before a noun they need の to directly modify it.
椅子が三つあります There are three chairs [chairs] [quantity of three exist]
三つの椅子があります There are three chairs [quantity of three chairs] [exist]