Merci de m'aider aviec le future simple

Aujourd’hui, c’est la veille deu Nouvel An.

Alternative: "c'est le réveillon du Nouvel An" (the word "réveillon" is mostly used for St Silvester's Day and Christmas Eve)

2022 est en train de arrivé.e !

The "en train de" structure isn't used as much as the English be + -ing, it's really for actions happening during the very seconds/minutes you're speaking. It's even more situational than in English. Here it'd be natural to simply say "arrive"

Ce soir, il y aura des feux d’artifice un peu près d’ici, aà huit heures, et aussi aà minuit.

Malheureusement, nous ne les verrons pas du balcon, mais nous les entendrons.

Je me coucherai tôt, pour preservouvoir profiter ledu matin.

Demain, je me promènerai sur lea plage près de chez nous.

Ensuite, peut-être que je nagerai dans la piscine, dans lae jardin de cette gratte -ciel.

"peut-être" as a first element triggers a relative clause, so "que" is needed

Ensuite, Je travaillerai aà/sur mon ordinateur, et je lirai un livre, et ainsi que des magazines.

"ainsi que" to avoid repeating "et"

Nous boirons du thé ensemble, mais thela plupart du temps, [nous feraisons nots propres activities lui meme.és ?]

I'm not sure I understood the end, I corrected "we do our own activities"
Such a sentence indicates an habit ("la plupart du temps"), and thus would be in the present tense

La nuite soir, nous cuisinerons ensemble et nous regarderons nNetflix.

This sentence is only valid if you're talking about what you'll do tonight specifically: if it's always like that (habit, once again) the present would be needed: "cuisinons, regardons"

Nous avons peur de sortir, car le COVID-19 se propagera dans le ville.

"se propagera" would mean it's not spreading yet but will start today (which is a bit strange) so I'd use the present tense once again, and even of the case of a propagation starting today, the verbs would be: "nous AURONS peur de sortir [...] le COVID-19 se propagera"