So much this. The rule of thumb is: avoid SFP-RJ45 converters at all costs, you'll be burned by them (literally and figuratively). They all are little snowflak

So much this. The rule of thumb is: avoid SFP-RJ45 converters at all costs, you'll be burned by them (literally and figuratively). They all are little snowflakes. Compatibility is hit-or-miss. They run hot. They eat more power. They're finnicky. Heck, they plain out lie about what they are (I've got some that pretend to be fibre with 3m of copper, sure). So yeah, DAC it is for patch, fibre for anything more.