Amanda Holliday has always sold only green ships and sparrows throughout Destiny 2 and the only way to get good ships and sparrows is to do activities like gambit and strikes, or level up and get a vehicle from Tess Everis. Amanda Holliday should sell better vehicles because she is the shipwright and because she doesn't sell better vehicles she is one of the least used vendor's for things other than quests. Amanda should also have her own exotic ship you can earn by doing a hard quest line or it is just very expensive.