Some people prefer the ostensibly calm lifestyle which prevailed during ancient times whereas others consider their current lifestyle the best which has ever existed.

Whereas others consider that the current lifestyle is the best that has ever existed.

This was a sentence fragment so I deleted it and appended it to the previous sentence.

I believe that my lifestyle is easier and more comfortable than the one my grandparents experienced during theirhad when they were youthng.

Firstly, technology has made everything easier.

Thus, people can know almost instantly what is happening inaround the world.

Not only is tTechnology isn't limited to computers and phones, but: it's also includesd in home appliances.

Currently, hHaving machines at home is somewhat usualnow almost ubiquitous.

However, notNot very many people, however, could afford a TV or a refridgerator seventy years ago.

Aside from that, Colombia currently, Colombia is definitely safer than it was fifty or seventy years ago.

Such was the insecurity, that people feared leaving their homes.

Drug lords were genercreating chaos in the cities.

It seemed that not even one soul one was safe in Colombia.

Finally, globalization has given me access to opportunities my grandparents couldn't even think ofimagine.

Presently, individuals can work for an American company even thoughtif they do not live in The United States of America.

There was an unbelievable lack of opportunities back to when my grandparents were young.

Therefore, I admire my grandparents for being able to surpass successfully surpass theose difficult times.

Whereas others consider that the currentmodern lifestyle isto be the best that has ever existed.

Thus, people can know almost instantly what is happening inaround the world.

"in" is grammatically correct, but "around" sounds more natural

Phones have allowed individuals to communicate with each other from anevery part of the globe as well.

Not only is technologTechnology is not only limited to computers and phones, but - it also includes home appliances.

I'm actually not sure about the - here. A : or a ; might be better

Currently, having machines at home is somewhat usualcommon.

Aside from that, currently, Colombia is definitely safer currently than it was fifty or seventy years ago.

This country has suffered a notorious amount of violence throughout itsin modern history.

Grammatically correct but the correction is more natural.

Such was tThe insecurity was such, that people feared leaving their home.

Guerrillas were going on a killing sprees in the countryside.

"a killing spree" is if there was only one

Drug lords were generatcausing chaos in the cities.

Grammatically correct but unnatural

Finally, globalization has given me access to opportunities my grandparents couldn't even thinkdream of.

More natural this way.

PresentlyNow, individuals can work for an American company even thought they do not live in The United States of America.

"now" gives a contrast to the past. "presently" denotes that this could change in the future.

There was an unbelievable lack of opportunities back to when my grandparents were young.

Currently, my nativeMy country is less dangerous than before.

Globalization has allowed me to takgiven me opportunities which were impossible to takedid not exist a couple of decades ago.

ThereforeWith that in mind, I admire my grandparents for being able to surpass successfully theget through those difficult times.

"Therefore" is the directly conclusion of something. I don't think it works well in this context