I tried a startup, a small legacy software comp like yours, a 5000+ people corporation, and a shitty dev shop and an international regulatory body

• Startup is hit or miss
• 5000+ corp has diversity policies that protect you but outside of those they won't care
• Shitty dev shop will be full of transphobes but they'll never show it to your face
• Smol old software company will do everything to preserve the good vibes of the office, if they hire you it should go smoothly
• Big international gov has eastern european/greek/balkans/portuguese devs and they come with their religious beliefs and not super cutting edge beliefs about gender. They'll have diversity policies but way less progressive than a private company - the bare uncriticizeable minimum, to cause the least amount of waves. Safe, no risk, and safe again.