1. Missing the article before "morning". After having spent the whole morning or a whole morning (works equally well here). "walk for relax" is incorrect. You'd probably want to say "I want to have a relaxing walk this afternoon", or "I want to have a walk to relax this afternoon". Something like that.
2. "at the theater" not "in the theater". There's a distinction on the purpose you're there for, it's a bit tricky, you'll probably need to Google this one a bit. But it basically boils down to "in the theater" as being "in a building" versus "at the theater" as being "entertained at this building". Sometimes they're interchangeable, especially when used colloquially (think "in da' house" vs. "at my friend's house"). It gets tricky. But in a classic sense you want "at the theater" there. Then "night" is misspelled. Also pretty sure you don't need commas around the theater. Also "glimpse" is a short viewing of something, pretty sure you were there to watch the whole show. Is "Lucy" the name of the show or the name of the actress in the show? Was she on for just a bit?
3. Looks good. But make sure you know the difference between everyday and every day (one word vs. two) as there are nuances there as well.
4. ✓
5. Grammatically ✓. But you don't really need to put the virus name in quotes, and you'll need to capitalize it. Also it's internationally referred to as COVID-19 (formally nCov-2019), I think. But I'm being overly pedantic here :)
Stay safe, Susan!
Cheers,
Gennady.