The HP EliteDesk 800 G4 TWR with Intel Core i7-8700 supports M.2 SSDs, but only PCIe Gen 3.0, as the processor and motherboard do not natively support PCIe 4.0. The WD Blue SN580 is a PCIe 4.0 NVMe SSD that is backwards compatible with PCIe 3.0, meaning it will technically work in your PC, but you will not get full PCIe 4.0 speed, but will be limited to PCIe 3.0 level.

If you want to install an M.2 2280 SSD from Kingston, this is generally compatible as long as it is an NVMe M.2 SSD and your motherboard has a suitable M.2 slot. The WD Blue SN580 is therefore compatible, but the speed advantage of PCIe 4.0 is not utilised.

Recommendation: You can use the WD Blue SN580 without any problems if you want a fast 1TB M.2 NVMe SSD. The performance is limited by the PCIe 3.0 interface of your PC, but the SSD is technically compatible and works reliably.