If current top-of-the-line PCIe 3.0 NVMe SSDs reach peak sequential read/write speeds of around 3,500 MB/s do not cut it for you, maybe save up for the upcoming XPG Sage from Adata that promises to deliver double the performance, at least for read speeds. The included Innogrit Rainier controller is also the first to break the 1 million mark for sequential write IOPs.
https://www.notebookcheck.net/Adata-reveals-PCIe-4-0-XPG-Sage-NVMe-SSD-with-1-million-IOPs-and-7-000-MB-s-speeds.449510.0.html