Fall/spring wedding guest dresses

Looking for advice:

1) dresses for a mother of the bride
2) with sleeves
3) from reputable brands

I’m finding beautiful frauds through regular google searches using key words that reflect that I’m a grown woman, size 12/14 looking for flattering dress options from real stores.

I think my hang up on having my arms covered may be tough to find because it’s summer.

Any leads would be appreciated
Thank you!