For the DPP to work for us, we need our setup to be able to connect with multiple suppliers, on multiple tiers. We looked at blockchain, yet have not been convinced that blockchain will break through soon enough. Are there alternatives that can get us started in the right direction without running the risk of having to reinvest after a few years?

Yes, there are. We have experience with several solution providers that enable exactly that: connecting multi-tier supply chain and life cycle contributors for your use-case purposes, including the post-sale part of your product life cycle. If in the foreseeable future blockchain becomes a viable and commonly accepted platform for DPP, the logic that you will have built up will still be valid, valuable, and necessary, not only for DPP but also for your other identified upsides.