Is it the same projects/ code for all clients? If so do they get the same built product? 1 backlog. Different code for different clients? Many backlogs. Proj

Is it the same projects/ code for all clients? If so do they get the same built product? 1 backlog. Different code for different clients? Many backlogs. Projects share code base maybe? Then you need Prioritization, planning and if you don't have that as a prerequisite then do Kanban maybe. It sounds like you cannot split the team and depending you could just have 1 product owner or a proxy PO. If clients need to approve designs that's design and backlog grooming- once the story is ready move it into a ready state (tag or state attribute) If you're reactive then kanban works better than sprints but of course depends on your environment, product/project mix, support vs product dev, and team composition