Did you know that you can edit Photoshop Smart Objects without using Photoshop? This was something that we discovered recently when working on a project for a client.
A full video tutorial of how you edit the Smart Objects using Affinity Photo can be found here. It works exactly the same in Affinity Designer as well.
Alternatively if you are looking for a free way to edit Smart Objects it is worth taking a look at Photopea. One issue I have found with using this online image editor is that it struggles to open larger Photoshop files but works fine for smaller ones and is easy to use, so worth checking out if you can’t afford the Affinity Software or Photoshop.