^ this.Asio load, what is that? Driver load? Asio has to do with getting audio in and out of the software. Your cpu is involved. More plugins means more cpu and asio doesn’t touch your plugins but if both plugins and asio are using cpu then....
I suspect you need to run a larger buffer for all you’re plugins
I doubt you need to run at 128, and really, the brand of interface will not have much to do with your latency issues. The RME and Apollo are both high end interfaces. Like I mentioned, even something like the Steinberg UR22 will suffice, it actually has zero latency monitoring. I used to run 150+ tracks while scoring top pic without issue on my old i7 2700k and Cubase 7. If you go Thunderbolt, running at 128 will be a non issue, but I doubt you really need to go down that road.