You'd probably have to find a program that uses OpenCL.
ECT doesn't seem to cause much CPU load, typically less than %20 on my machine so you could speed things up by running concurrent tasks.
Example:
.\timeit.exe .\ect.exe -9 .\20221224-topaz-denoise.png
Processed 1 file
Saved 1.95MB out of 12.34MB (15.7650%)
Version Number: Windows NT 6.2 (Build 9200)
Exit Time: 12:32 am, Wednesday, January 11 2023
Elapsed Time: 0:01:28.952
Process Time: 0:01:28.937
Five concurrent processes on the same file, (five different names):
.\timeit.exe .\ect.exe -9 .\20221224-topaz-denoise(x).png
Processed 1 file
Saved 1.95MB out of 12.34MB (15.7650%)
Version Number: Windows NT 6.2 (Build 9200)
Exit Time: 12:39 am, Wednesday, January 11 2023
Elapsed Time: 0:01:42.891
Process Time: 0:01:42.703
Time to process increased by 14 seconds, (this was the same for all processes give or take a few ms), CPU utilization was still under 60% so still plenty left for doing other things.
So for the cost of an extra 14 seconds I got a 5 fold increase in files processed, files had the same properties of course but it should still scale similarly.