Based on other posts here I’d look at the QNAP QM2-2P10G1TB or QM2-2P2G2T (if you can live with dual 2.5G). The Synology E10M20-T1 does not seem to work with the full build, it may be locked to Synology hardware in some way, the Sonnet is old and does not have good reviews. I don’t know about the Asusstor, but it should physically fit. The QM2-2P410G2T is going to be a tight fit at 187mm; I don’t have an HL4/8 but you could measure yourself and see what you think.
https://forum.45homelab.com/t/pcie-card-with-ethernet-and-nvme/2506/6
https://forum.45homelab.com/t/hl8-prebuild-does-not-work-with-synology-e10m20-pcie-card/3073