I think the cake is irrelevant. If you weren't able to deliver it, and she didn't want to pick it up, if she really wanted to make it work a 3rd party could get involved to handle logistics (maybe even another friend, mutual perhaps)

At the end of the day, you didn't make the cut, and she needs to be comfortable enough to realise she doesn't make yours.

You can still be friends, but realise you both aren't as close friends as you previously believed. Wedding guest lists are always complicated matters and that's before even considering the groom's side.

I like to try to keep the perspective that it is a great honour to be included, but try not to take it personally if I am not included.

It does suck that Covid complicated matters further. If you are interested in giving her the benefit of the doubt, its entirely your call. I would try to remember she really did consider you close enough friends to be asked a favor, and an invite.