Sorry to hear about your struggles. 8.3 is a little high but not outrageous by any means. I was 7.9 last November and I believe I was 7.3 when I conceived - a bit higher than my doctor wanted but she had no concerns. My doctor actually doesn't like to see people below 6 when pregnant because she feels it's likely too many lows are happening in that case. My last A1C at 28 weeks was 6.3 - I don't get anymore while pregnant because my doctor also feels they're unreliable in later pregnancy. Different doctors definitely have different standards for what they want to see. It's also entirely possible your miscarriage was unrelated to your diabetes.
It sounds like you're on the right track and doing everything you can to start getting a bit tighter control. Pregnancy with T1 is a roller coaster and even though the guidelines are strict, they're impossible to stick to all the time.
I initially didn't want the pump because of having something attached to me, but 15 years later I can't imagine life without it. I often hide mine in what I'm wearing and rarely get asked about it anymore. Most people used to think it was a cell phone or pager when I used to wear it obviously.
Definitely check out the pregnancy toolkit -
https://www.jdrf.org.uk/news/latest...ncy-toolkit-for-uk-women-with-type-1-diabetes
I also got the book Balancing Pregnancy with Pre-Existing Diabetes. It's from the US so I wrote in mmol numbers. At the start of pregnancy I found it stressed me out a bit to read it, but more recently it's been a help.