There are cedars, and then there are cedars. Did you check the nocks on all your arrows to make sure they are on straight? A crooked nock will throw your arrow way off. A crooked point will have an effect as well, but not as much. Also, the shafts may or may not be spined the same. Just because someone put a 50-55# tag on them doesn't mean they're all 50-55#. Of course you need a spine tester to find out.
To find the culprits in your current batch, write a different number or letter on each of your arrows. Then keep track of the fliers you're getting. If it turns out being the same one or two numbered arrows, there's something wrong with those arrows (See above.) Of course, poor arrow flight can also be caused by inconsistent release, form, etc,
Wood arrows are more difficult to work with than carbon or aluminum. Shafts aren't as consistent in spine or weight (or grain) as carbon or aluminum. To do it right, one needs a spine tester, grain scale and good tapering device.
Carbon or aluminum may be a better choice, particularly if you're just getting in trad archery. Once you find a carbon or aluminum shaft that works for you, the work is pretty much over. Might try some of the combinations already offered. Good luck.