I prefer to spend money on experiences, like travels, studies, movies, etc.

You can either write "to spend" or "spending". If you don't use the "-ing" form of a verb, then you have to add the word "to" to the un-conjugated verb

"experiences" needs to be plural here; I can't think of the rule, but if it's singular here, it sounds like work experience (简历）rather than having fun.

Adding "etc" is not required, but it sounds better. Usually in English, when we write a list, we can either use "and" with the last one on the list, or use "etc" (等等）

It'll be a new year afterin 5 days.

When we are using a specific amount of time, we will use "in". For example: "In 5 minutes, the food will be done", "In 2 years, I will graduate", etc

We use "after" with times if we are not using specific numbers, such as "After next week, it will be 2021", "After tomorrow, I go home to see my family"

I'm thinking about what I have done this year.

We often use the prepositions "of" or "about" with the verb "to think"

think of = "想起来“

think about = “想某事“

Thiseat's a question.

And a bigger question is what I should to do next year.

Should + a verb, we don't use "to", for example: "I should eat something", "I should go home".

I have many things that I want to do and that I should to do, but some of them are very dependingent on the pandemic situation, for example, my travel plans.

Same thing here, with "should", drop the "to" after it. Also, it is common to rewrite "that" after an "and"

The phrase is "to be dependent on" or "to depend on". So you could either say, "some of them depend on the ..." or "some of them are dependent on the ..."

I prefer to spend money on experiences, like travels, studies,y, and movies.

It'll be a new year afterin 5 days.

I'm thinking of what I have done this year.

Thisere's a question.

This would not normally be appropriate, but when someone is feeling contemplative, one might informally say something like "There's a question" for emphasis. (In this case, it emphasizes the "what have I done this year" question.)

And a bigger question is what I should to do next year.

I have many things that I want to do and I should to do, but some of them are very dependingent on the pandemic situation, for example,such as my travel plans.

I prefer to spend money on experiences, like travels, studies, and movies.

It'll be a new year afterin 5 days.

I'm thinking about what I have donedid this year.

"what I accomplished/achieved" would be better if you are talking about achievements instead of just normal day to day things

Thise's aat's one question.

changed to one instead of "a" because your next sentence has another question

And a bigger question is what I should to do next year.

I have many things that I want to do and that I should to do, but some of them are very dependingent on the pandemic situation, for example, my travel plans.