You're friend is obviously struggling (aren't we all!)but she is out of line attacking you and blaming you for lockdown etc. You're better off without that nonsense in your life, and I would worry that she would make a scene at the wedding or something. It's so tough when it's a good friend though.
I'm sorry OP, it's really hard. My best friend is a bit the same, and it's so draining, First she didn't believe in covid at all, then started talking about Bill Gates 5G etc. then it became, oh it's just a cold what's the big deal, now she thinks we're all sheep for going along with things.
She doesn't want to wear a mask, fair enough, she just avoids going places where she has to, but she's so angry all the time it's really uncomfortable.
I do sympathise a bit with her, as I think it's something to do with loss of control, which we are all feeling a bit. Also, my friend went through a bad few years and was put on anti depressants, which didn't work, and then started to look at alternative medicine and reiki to help herself out of a bad place, which really worked.
She talks about how the mask makes her feel like she's being muzzled, so I understand she's anxious and she doesn't trust pharmaceutical companies anyway.
Like you, my friend started sending me links to some conspiracy stuff - at first I was very non-committal, now I just don't really reply. She knows I don't agree, and thankfully we can still meet up and talk, we usually try and talk about other things, but it's difficult and has at times made me not want to spend time with her, as it's too negative.
The key is to be able to agree to disagree, but its hard when someone you care about seems to be going down a weird path.
Anyway, sorry for the long post, just wanted you to know you are not alone!