This iwas caused by COVID-19.

Before the pandemic, we generally met myour friends at a local bar,s and drank beer and Soju without no restriction.

Saying "a local bar" is technically correct, but it implies that everyone went to the same bar. If everyone went to a bar in their own area, you should say "local bars."
The comma I deleted was to correct the grammar according to the "rules," but native speakers might use that comma.

But now, the virus is thea major problem, and many people are drying around the world.

That’s why our government makes strict rules to control the spreading of the virus.

Alternative:
That’s why our government makes strict rules to stop spreading the virus.

We can only meet lessin groups of fewer than 4 people, and we must wear a mask everywhere.

"Fewer" is used to describe a smaller number of a pluralized noun (like people or minutes), while "less" is used to describe a smaller amount of a non-pluralized noun (like happiness or time). Many native speakers would still say "less" in your sentence, though.
I added "and" after the comma because it was a run-on sentence without it.

Restaurants and bars shouldmust close before 10 a.m.

You should use "must" to talk about rules and "should" otherwise.
Also, do you mean 10 p.m. (night)? I am just guessing from context.

As a result, we are unwilling to have any gatherings now.

I hope the pandemic conmes to an end soon.