I am planning to hold a meetingget-together with my friends next week.

Nothing is wrong with your original sentence! But you can also say "I'm planning to have a get-together with my friends," or "I'm planning to meet up with my friends," as well. The phrase "hold a meeting" in English sounds very formal, like you are going to have a meeting with your boss.

One of my friends says that the pandemic situation is not likely to become badget worse, but I should prepare for the worstto delay or reschedule the meeting just in case.

Just stylistic changes, to provide more context.

Just yesterday, thewe saw a record number of infected people got the highest record during the situationduring the coronavirus pandemic.

I am planning to hold a meeting with my friends next week.

Your sentence is already good, but it sounds a little formal for a casual situation. You could also say:

I am planning to meet with my friends next week.

One of friends says the pandemic situation is not likely to become bad, but I shouldwill prepare for the worst.

Or: One of friends says the situation is not likely to become bad, but I will prepare for the worst.

Just yesterday, the number of people infected people gotwas the highest record during the situationpandemic.

Or: Just yesterday, the number of people infected was at an all-time high during the pandemic.

So, in the worst-case scenario, we might have to meet after splitting us into 2 groups.

In the meantime, we are also prepareing our own masks and self-test kits to prevent emergencies.

Let’s keep our fingers crossed that wethings don’t head south.

One of friends says the pandemic situation is not likely to become badworse, but I should prepare for the worst.

Just yesterday, the number of infected people gotwas the highest record during the situation.

In the meantime, we are also prepareing our own masks and self-test kits to prevent emergencies.

Just yesterday, the number of infected people gohit the highest record duringof theis situation.

I only corrected this just to make it sound a bit more natural, but no one would be confused if you said the original sentence.
In a purely strict grammatical sense, your original sentence implies that the infected people got some sort of record (any record) during some sort of situation (COVID related or not).
So it was just a matter of specification. Of course, we all knew you meant COVID but I'm just nitpicking

Let’s keep our fingers crossed that we don’t head south.

"...it doesn't head south." sounds a bit more natural in terms of implying the situation of COVID, but your sentence still works as it also really means us, as humanity right now in general, in this particular pandemic situation, and the hope that the cases don't spike again.