I am also not great with timing. I probably could get there with enough practice, but I haven't bothered to train parrying because it's iffy and there are workarounds.

I started off using tower shields because of their better blocking stats. Then I realized that I could get even more damage mitigation by not being hit, and that while blocking, I'm not attacking, but I am losing stamina and a small amount of health. The greys aren't just annoying, they're also teaching you something if you would learn. Don't stand still while things are wailing on you, even if you really want to get that third strike in. If you depend on the shield too much to face tank things, you're probably going to get into trouble.

So, now I pretty much only pull out the shield for archers, at least until they're close enough for me to whack them. Then I put it away because being slow is bad.

For the poor man's parry, get an atgeir. The secondary spin attack will stagger almost anything in range, without worrying about timing as much. They still have to be in range of course. It does eat stamina, so eat well, and do the greyling walk around as needed. Don't try to spam attacks any more than you need to. It works brilliantly against trolls, wolves and draugr, and not so great but doable for things that are resistant to pierce. You will likely need a secondary weapon, but when it works, it works.