Thus, we should look for blended of a fast pace and a slow pace in our life.

"Thus" implies that you said something and you are referring to it in this sentence.

Sometimes withinhile working, taking some time can help us to reboot our energy.

I think something is missing here. Maybe "taking some time <off> can help us to reboot our energy"?

Moreover, if we spend a small amount of time forat a slower pace, throughby focusing on ourselves after work, we can achieve more colorful relationships and private life.

In the future, we should not be too obsessed too much by the competitions and the successes, some. At times let’s take some time to reflect on ourselves and live a happy life.

Thus, we should look for blendeda balance of a fast pace and a slow pace in our life.

"A fast and a slow pace" allows the sentence to flow more smoothly. Balance suits this context more than "blend" if that was the meaning you wanted.

Sometimes within work, taking some time can help us to rebootregain/recharge our energy.

"Reboot" is often used for systems or technology so either "recharge" or "regain" makes more sense in this context. It is not very clear what you mean by "taking some time". Maybe "taking some time to slow down" is what you meant?

Moreover, if weby spending a small amount of time for a slower pace, throughslowing down and focusing on ourselves after work, we can achieve more colorful relationships and a/an (adj.) private life.

Just corrections to improve flow, "by spending" can be used instead of "if we spend". In general, when writing a sentence where an action leads to an outcome you say "by (action)". "Small amount of time for a slower pace" is not grammatically correct, you should use "at" instead. However, "slowing down" keeps the same meaning and is more concise. Adding another adjective before private life will make the sentence flow better and sound more native.

By adjusting two sides ofour pace between fast and slow speeds, we can achieve twoboth goals in our work and relationships inat the same time.

"Two sides" doesn't work in this context, usually you use two sides when referring to arguments or debates i.e. two sides of the debate around veganism. "Both" works better and you need "our" again before "work and relationships". It's always "at the same time" not "in the same time" so just keep that in mind. Also, if you would like you could use the word "simultaneously" which means at the same time. So in that case the sentence would be "By adjusting our pace between fast and slow, we can achieve both goals in our work and relationships simultaneously."

A slower pace of life is a smart lifestyle, aand well-balanced lifestyle in thea competitive modern society.

In the future, we should not be obsessed too much by the over competitions and the successes, sometimes let’swe should take somthe time to reflect on ourselves and live a happy life.

The use of "by" with obsess is incorrect, usually, you would use "with" (i.e. we should not be obsessed too much with competition and success). Saying "obsessed too much" can be redundant since "obsessed" already implies overthinking or overdoing so "too much" is unnecessary. Saying "the competitions and the successes" in this case is grammatically incorrect because you are not talking about someone's specific competitions and successes, so using "the" is unnecessary. Since you are speaking more generally, saying "competition" and "success" in the singular is more correct. "reflect on ourselves" is also redundant since reflection already means that it is done to oneself!

Thus, we should look for a blended of a fast pace and a slow pace in our life.

Moreover, if we spend a small amount of time forat a slower pace, through focusing on ourselves after work, we can achieve more colorful relationships and private lifeves.

Private lives plural as the subject "we" is plural.

In the future, we should not be too obsessed too much by theby competitions and the successes, sometimes l. Let’s take some time to reflect on ourselves and live a happy lifeves.