They're Samsung memories, as mentioned in OP.
Samsung K4G80325FC · 113-58085SSD2-W90
I use HiveOS on my rigs so, no access to wattman and Afterburner, but on HiveOS we can also edit memory timings. The thing is that I'm not experienced enough to make it right.
I thought one can flash bios right in hiveOS interface? Give SMOS a try or minerstat, you should be able to flash bios in this OS instead of looking for other ways, it would have been so easy if you are using Windows OS because I have the right settings for samsung memory RX580 GPUS to get 30mh per second