Hi,
Definitely looks like those NICs are not happy with that driver/firmware combo.
VMware VCG/HCL indicates that firmware has not yet been tested and certified
https://www.vmware.com/resources/compatibility/detail.php?deviceCategory=io&productid=41156&vcl=true
Latest tested FW is: 20.06.05.06.
Maybe try a rollback and test the official tested combo of Driver bnxtnet version 20.6.302.0 and FW 20.06.05.06.
"Dell Lifecycle Controller - Firmware Rollback" looks like it will do the trick:
Video + Documentation from Dell below:
Failing that, suggest reaching out to Dell for suggestions on tested configurations and recommendations for known good driver/firmware combos for 6.5.