We've already answered these questions above...
You definitely should not reduce to twice a week just yet. You don't actually ever need to, but you should get symptoms well under control in a consistent/ongoing way - and then experiment to see what your body can manage.
As for systemic HRT, it depends. If you take a decent dose of systemic estrogen, it means your body usually doesn't need any at all locally. That's what happened to me. I can't tell you what a total fcking pain in the ass it is to be applying moisturisers, estrogen creams, pessaries, avoiding sex, having things leaking out of you blah etc. I am ecstatic that on a decent dose of estrogen, I no longer need anything locally at all.
As for 'without releasing estrogen into the blood stream' - why would you want to avoid that? You want to release estrogen into the blood stream because it will decrease your risk of dementia, diabetes, insulin resistance, bowel cancer, osteoporosis, cardiovascular disease and more besides. It's not a bonus to avoid estrogen in the blood stream, it's a drawback. The number one killer of women worldwide is cardiovascular disease.
Your whole body needs estrogen, not just your vagina.