Earlier quoted context omitted.
I own one also, while I do recommend them... I would also recommend some caution if planning to use Linux I'm not sure if this is a common/repeat thing, but for mine I need to maintain a build of the Realtek kernel modules out of tree If I try to use the discovered/automatic/inline driver... it'll drop out if I try to saturate the link. It's only when I blacklist this module and compile/use the one from Realtek that…
What distro and kernel version are you running on there? The Realtek 2.5G NICs should work natively with a recent kernel.
It's quite odd, this is with Fedora -- the current/latest release for about the past year (34 through 36).
It's seen quite a healthy number of 5.x kernels, but every time I try to go without I reluctantly have to build it again
It'll work fine, for a time, but when I really put stress on that link it'll drop
Edit: This is trained at multi-gig too -- going to a 10GbE Mikrotik switch.
I haven't tried testing reliability at 1G -- it's probably better, but I'd like the speed... I still have yet to try a 6.y kernel on it