1. Is “ON your feed” correct? 2. Can we use feed as a verb? Does “TikTok always feeds me some poor contents” sound right?

Yes, "on your feed" sounds natural to me. Yes, you can use feed as a verb, though I believe it's just because "feed" the verb already meant "distribute media to"/"supply someone with"/"satisfy" before "feed" the noun came to mean "list of new content for you to browse". I would restate your sentence as, "TikTok always feeds me poor content" - "content" should be singular when referring to media content, and the "some" qualifier is optional, depending on context, I would say.

1. "On your feed" is correct. replacing "on" with something like "in" would sound weird 2. I'd say you can use feed as a verb here, but it sounds a bit strange. I like how the text in the picture says "put...on your feed" rather than "feeds you", but it's not incorrect 3. content should not end with an 's', and the 'some' is optional. I'd probably prefer to omit it to read: “TikTok always feeds me poor content”, or taking my suggestion from (2): "TikTok always puts poor content on my feed"

Most social media sites have an algorithm that they tailor to the user that decides what you see when you scroll. In English, this is mainly referred to as your 'feed.' So yes, you could tell someone about something you saw 'on your feed.' You might also see 'on your timeline' when talking about Facebook. Your example as a verb is where the word comes from. The algorithm is feeding you the content.

"On your feed" is correct, think of it like something being on a page or on a screen. You could use feed as a verb, but it's not very common in the context of social media. The verb "to feed" means to give something for the purpose of consumption, most commonly referring to food. A more natural way to say what you want would be "Tiktok always shows me bad content." It wouldn't be grammatically wrong to say "Tiktok always feeds me bad content," but it would have a negative feeling, maybe like you're making a point about Tiktok's algorithm forcefully showing you bad content. "Content" isn't usually plural in the context of social media.

*In* your feed.

"On" is allowed when you are intended to imagine something coming from a higher place to land on something else. Feed is a verb, but a slight odd one in this case. There's no particular reason for that and it isn't actually wrong.