I understand your frustration with shaving and acne. I feel like I have a very similar problem. Sometimes I feel like avoiding irritation is impossible if I want to get an acceptable shave. I also feel that shaving is an extremely subjective topic. The things that help me with this problem may or may not help you.
If shaving straight down doesn't do the job as well as you'd like, try multiple passes across the grain in different directions. Do your first pass with the grain, as always. The second pass would be perpendicular to the grain, and the third pass would go opposite the second. So, assuming the grain of your beard goes downward, the first pass would be from top to bottom, the second pass would be from left to right, and the third would be from right to left. You can angle the "across the grain" passes so that they pull ever so slightly upward if you really want. Some people think that multiple passes can be irritating, but it depends on how you shave and what your beard it is more than the practice itself. For me, I find that multiple gentler passes are more effective and less irritating than one go with the haymaker.
I'm unsure of your reasoning with regards to shaving every other day. I would rather have an ~okay shave every day than a great shave one day and a scruff the next. That's probably personal preference. Again, for me, I'd rather do multiple gentler shaves than fewer close shaves. I find it to be far less irritating. I feel that my skin isn't necessarily irritated by shaving, just by shaving too hard or badly. There is some sort of threshold or something.
I do notice a significant improvement in the closeness of my shave, and the feel of my skin when I use shave oil. Well, I guess it's not technically shave oil (I put a layer of jojoba oil on under the shave cream) but it does the job.
I use a "double-edged safety razor" and it seems to work for me, but it's more for the price (cost of refills is negligible) than the quality of the shave. I do find that it makes multiple passes a little easier to bear (being that there's only one blade on my face at a time).
Do you think that your acne is related to shaving a certain way? Have you experimented with this (aka only shaving with the grain for a few weeks and seeing how it works out). Is your acne related to ingrown hairs, or is it just plain old acne?