Hi,
Please, let's not exaggerate,
The thirteenth generation DELL PowerEdge systems, such as the DELL PowerEDGE 730s are starting to show the weight of their years but they are not yet scrap since they are openly in HCL for ESXi 7.0U3.
Systems of that generation were initially equipped with XEON E5-2600 V3 series processors introduced in Q3-2014 and then with XEON E5-2600 V4 series processors introduced in Q1-2016 thus it is one thing to say that that generation of systems were put on "end of sales" state during the first months of 2018, another to say that they were put on "end of life" state.
IMHO the OP has two choices, either to replace the existing hard drives with others of greater capacity or to resort to shared storage that, however, it would more easily protect the economic investment, given that in both cases it is not negligible. Then a lot also depends on the use model of those machines in the IT context of the OP because, for example, if those systems were used in a laboratory context there would also be other options.
Regards,
Ferdinando