I said I would share some videos and pictures of my n(National Day) holiday.

“My national holiday” is unidiomatic to me. You could change “national” to “National Day,” but personally I would omit it, or say “my long holiday” instead.

I spent more than onean hour preparing the video, but the only one I can show you is this short one: https://www.youtube.com/shorts/VD5lLYaUVVg

I’m having trouble correcting this because I’m not sure exactly what you mean. In your original wording, “the video” in the first part sounds like it’s not the same thing as the “short one” in the second part (the second part sounds like maybe you made several videos, but you’re only able to share one of them for some reason). But logically I think you probably mean it took you more than an hour to make the video you shared. If so, then here’s my suggestion:

“After spending more than an hour editing and narrating video clips, all I have to show you is this short compilation.”

I'm a bad recorder

The other corrector’s points are valid but is still something I would say/write. It doesn’t sound weird at all to me, it’s just casual. My family/friends could easily send this in a sms/chat message, but I wouldn’t use it in an exam/essay.

I also met many kind locals and had some nice chats with them, but I didn't record themany of it.

Original not wrong, I just like this better.

I spent more than one hour preparing thea video, but the only onething I can show you is this short one: https://www.youtube.com/shorts/VD5lLYaUVVg

Original wasn’t wrong but this sounds better to me

I'm a bad at recordering (my journeys)

You don't use -er in this kind of activity. "Documenting" is probably the better word instead of recording.

I said I would share some videos and pictures of my national holidayday off.

In American English, we would say "National Holiday" for a day off from school or work, but you wouldn't take pictures or videos of the National Holiday.

When I opened the album on my phone, I realized that I'm bad at recordingdocumenting my adventures.

Based on the next sentence, "adventures" or "experiences" would be good alternative words to use.

I came across so many wonderful things, so many vegetables, fruits, and fish that I had never seen before, but I didn't capture a lot of them.

Your original sentence implied that you didn't take any pictures or videos, but the YouTube video you shared at the end suggests that you did take some.

I also met many kind locals and had some nice chattalks with them, but I didn't record them either.

"Nice people" would probably more natural, rather than "kind locals" but it's not grammatically incorrect.

I spent more than one hour preparing the video, but the only one I can show you is this short one: video (https://www.youtube.com/shorts/VD5lLYaUVVg), but I wish I could show you more.