Are those APIs supported by all major browsers or is it Chrome(-ium) only? Even if those are supported, it will mean the users may need to update their browser to use the site (but maybe the support is implemented long ago and that's not much of an issue)

I see you answer that question for most of proposed APIs, but for some of them support is fragmented and/or present since 2025 and even 2026 for one. But at least it's not a single browser vendor lock