My approach starts differently from yours, and might seem pretty depressing to you, so apply some grains of salt and feel free to ignore.
I start from the notion that there's nobody who understands the whole me. Not therapist, not spouse, not siblings, etc.. We humans are pretty complex beings and we're also very different from each other. So I don't expect any one person to 'get' the whole me.
But different people understand significant parts of me. My siblings understand my childhood, so they're great to talk to when things happen now which bring that back to mind. Coworkers understand things relating to being a pretty hard core nerd (not a compliment in my age group). My spouse understands a lot, so is a good general person, but there are things about me that are in her blind spot. This is also true in converse -- things about my spouse (and everybody else) that I don't understand. So I am glad that my wife has friends. And that I have friends. No one person can understand everything for either of us.
So for tips, I'd suggest thinking smaller than a person or people to understand the whole you. A person or people who understand your love of (crafts, sports, beer, whatever), some other people who understand or at least are supportive of your transition, and so forth. Starting small and then you can build up (
This is, I understand, stereotypically 'guy' approach, and I'm a cis-guy, so that could be much of why it works for me. Then again, even guys are people, and even while people are different, we're not different species. Worth a try?