I had to prepare lunch for myself, because there weren’t family members in my house todayno one else was around.

"I prepared lunch myself " implies: I made lunch for everyone without their help
"I prepared lunch for myself" implies: I made myself a lunch

In that video they tried to make it, andThey were able to do it so I thought I might also be able to make it as well, too.

Looking at the Japanese version, "メンバーが挑戦してて、", the feeling I get is that the person on the show took on the challenge of making the dish, but it's unclear whether or not they succeeded until I read the next part, 私でもできるかも, and reason that if you say "私でもできる" they also must have できた, right? However, in many circumstances in English, "tried to" is going to anticipate a "but". Like, "They tried to make it but it proved too difficult."

"Try" can sometimes have some difficult nuances to navigate to where even a native speaker can be reprimanded for using it when they want to express an intention to do something, but it can come across to others as you not intending to put in sufficient effort, thus we have this phrase "Don't try. Do."

My proposed wording of "They were able to do it" has a nuance of the task not being easy which seems to make more sense to me.

Also, reading 私でも instead of 私も, I'm wondering if that has an "even I" nuance to it...

Anyway, I'm not entirely sure I understood your Japanese version so I hope I didn't change the meaning.

I watched the videos again, and tryhen tried to make it.

"I watched videos" implies "I watched various videos on the topic." But you can't say "again" in that case since they're different videos.
"I watched the video again" implies "I saw it exactly twice"
I was wondering between "watched again" or maybe "watched the video again and again."

I had to prepare lunch myself, because there weren’t any family members in my/the house today.

So I decided to try making a fluffy omelet rice.

I watched the videos again, and tryied to make it.

I made ketchup rice and put on the omelet on top.

I wonder if I wshould try it again tomorrow.