When I am browsing through YouTube, I findoften watch / look for a video clip that is about vlog made during a trip. When I am browsing through YouTube, I often watch / look for a video clip that is a vlog made during a trip.

If you use the present tense you need to add adverbs like often. You can use the past tense: When I was browsing through Youtube I found ...

Because of the pandemic, my friends also love watching theis video series over and over again. Because of the pandemic, my friends also love watching this video series over and over again.

your sentence is not wrong but is a little unusual. You could say : my friends have watched the video series over and over again

Unlikely the big cities, small cities have their own character and I am blown away by the charming locations. Unlike big cities, small cities have their own character and I am blown away by the charming locations.

Unlike is a preposition followed by a noun. Unlikely is an adverb and needs a verb. Don't use 'the' when meaning is 'in general'

I will travel to these cities after finished this pandemic has finished. I will travel to these cities after this pandemic has finished.