They both Turbo to 3.7GHz, so all else being equal, you are unlikely to see much difference per core, and indeed, Passmark shows an ~8.8% increase in single thread rating for that ~23% clock increase from 2.1GHz to 2.6GHz, and yet going from 12 cores to 16 cores resulted in ~0.3% decrease in rating. Keep in mind,the sample size is exceedingly small (1 and 10 results).
Without knowing your use case, it's very difficult to make a good recommendation, so I'll make a recommendation of unknown quality:
If you will be running Windows Server VMs, get the 6130. You'll have 32 vCPU instead of 24 vCPU. Since they both turbo to 3.7GHz, intensive users won't see much difference and casual users probably won't feel the difference. But what really leads me to make this recommendation, when running Windows VMs, is that licensing costs the same either CPU. Microsoft requires minimum 8 core licenses per CPU and minimum 16 core licenses per machine, so you will have to license 16 cores regardless.
The question then is how many Windows VM's do you expect to run? List price for Windows Server Datacenter for 16 cores is $6160 and you are licensed to run an unlimited number of VMs (not equipped to run unlimited, but still, many VMs :).
Windows Server Standard is cheaper if you are running 12 or less VMs: $5832 gets you licensing for 11 or 12 VMs, and decreases in price at 10, 8, 6, 4, 2 VMs, with 1 or 2 VMs costing $972. To license 13 or 14 VMs, WS Standard lists for $6804, so there it is. More than 12, Datacenter is cheaper, less and Standard is cheaper, but the point is, anyway you license it w/Microsoft, the 12 core CPU costs the same as the 16 core because you must license 16 cores minimum.
Generally, given the relatively small difference in performance per thread, having 32 vCPU available is better than 24 vCPU for VM hosting 12 - 15 people simultaneously, but it is possible that your particular workload would benefit from a higher base frequency more than an increased vCPU count, although I doubt it, seeing as having 15 simultaneous users results in < 2 vCPU per user on the 6126, while the 6130 gives you 2 vCPU per user + 2 for the host.