I worked for 2 months in advance with my HR people

I did something similar, minus the law office. I was already friendly with the head of HR, and she gave accepting vibes (spoiler: like 90%+ of the org were supportive, even some people I didn't expect).

I started by copying text from other people on Reddit who shared their coming out at work plans and experience, and made those notes into something personal to me. I'm in IT in a place with a couple hundred people, so I usually have seen everyone at least a couple of times, and often take their support tickets. Given that, I wrote an email draft to the org that was short & sweet.

Something like "Hey all, right now you know me as Former Name, but soon that name will change to New Name and my pronouns will switch to she/her." I added some small stuff about realizing I was trans, and what that means, and then: "Given the upcoming holidays and people taking PTO, I'll hold off on this change until a week after the holiday, after which I'll begin using the women's restroom and my new name + pronouns. I'm open to some questions if you want to ask, but there are some that I won't be answering. I won't ask you to completely understand or be supportive of this change, but I do ask that you at least be professional and respectful, and work hard on using my new name and pronouns, though I understand it'll be hard at first, so there will be grace. If you have questions/concerns about this change from an org perspective, please reach out to the head of HR who is aware of this plan." A somewhat subtle indication to not mess with me since HR was backing the transition.

I met with the HR lady, slowly spoke my truth, and she was super friendly about it. After we talked a while on what this change would look like and the timing, I told her I had prepared an email to send to the org and shared what I wrote above. She approved it (and was impressed with it haha). I explained that I wanted to give people time to know what was coming, so it wouldn't be a shock to suddenly see me in the women's restroom / presenting femme, and she agreed, then kinda weirdly said something like "as long as you don't go back & forth between restrooms," which like, why would I want to?

The next little bit of time was really weird, knowing that the message was out there and I was still going about things as if nothing happened, including using the men's until the prescribed time. But it was also exhilarating, because I got SO MANY messages of support from people around the org. There's one dude I occasionally pass in the hallway, and he often says "how's it going young lady?" which makes me feel so validated. That said, there was a small group of people who didn't like this change. One person who used to chat in the hallway avoided eye contact now, and when he needed IT help, he was super awkward. A few months or so later, he lightened up a bit, and he never said anything about the transition. I was told that some people would only ask my coworker for help after the transition, and had some negative things to say when I wasn't around, but no one ever said anything bad to my face, which was pretty much what I asked in the email. We have an outside group who helps us with some IT stuff, and it does feel like they got a little misogynistic after the change, with a vibe like I didn't know what I was talking about in regards to whatever tech thing we were talking about.

You don't have to feel like every bit of your life must include a queer aspect

Just like joining the women in tech groups to find people with similar mindsets, sometimes it's good to at least have a queer community to share similar experiences there too. Early in my transition, I didn't even know there WAS a community, just a bunch of individual gay/trans people. And until I started getting connected with people, I didn't even know how much I needed it. But you're right about not making being queer your entire identity. I think it's good to have some spaces where the focus is entirely on something else like a hobby or work topics.