Suggestions for a doorbell that unlocks with phone proximity but without internet

[nagisa]

Hello all,

I'm looking for a video doorbell for my fencegate. This is a single-family home, so it only needs one button. I reached out to some local places that deal with such items and came up with the following list of requirements:

1. Mounted outdoors (should be rated down to -30°C);
2. Two-way audio, video capability;
3. Ability to unlock based on proximity of a phone (think: NFC-like; if it matters, everybody here is using Android)
4. Its capabilities have to work without ever giving the doorbell access to the public internet (esp. no cloud dependency.) Connectivity is routable to the clients on the same "LAN" 24/7.
5. Powered by a wire (not battery); I have 24VDC and 230VAC in the mounting area. But in principle I have no constraints: I can easily procure different voltages and/or PoE and/or USB;
6. Open protocols or sufficiently extensive documentation to implement my own stuff; think RTSP, ONVIF, SIP or similar.

Additionally, but not required:

1. One relay for 24VDC (I can put a separate relay if needed);
2. Neat minimalistic appearance (e.g. I would rather not have a keyboard, an unnecessary display, etc.
3. Would prefer WiFi but I can figure out Ethernet (would eventually go over WiFi anyway, though.)
4. Relatively manufacturer app-free experience (although if necessary for just the setup, that's also fine.)

The local shops have either suggested nothing at all or variants of DS-KV6113 (which fails the NFC-like unlock experience requirement AFAICT.)

My own search have found me the following options:

1. Hikvision DS-KV6114-*WBE1 – phone unlock is based on bluetooth signal strength. Documentation does not tell as to whether internet connectivity is required to set this up; There's also this video which demonstrates the slick action that I want to achieve;
2. (Upcoming) Unifi G6 Entry – NFC phone unlock, but no comment from ubiquiti if those NFC cards will have a monthly cost like the Access TouchPasses for iPhone or not; Some phone app features likely require the unifi protect thingy to be enrolled with unifi's cloud, but notably if they do it similarly to Access, app would really only be necessary for setting up NFC unlock once (and could be deleted/disabled later);
3. Akuvox R25A/R20A/E13S – pretty much ideal except that the NFC functionality requires cloud deployment, my disappointment is immesurable;
4. 2N IP Style / IP Verso 2.0 – phone unlock is based on bluetooth signal strength (WaveKey) and/or NFC (MobileKey). Well outside of my budget range, so I didn't investigate much more.

Is there any other products I should look into? Does anybody know if DS-KV6114 requires the doorbell to have internet access for its bluetooth unlock functionality to work? I'm pondering if I should just bite the bullet and test this out on an unit from Ali… I'm also open to an idea of multiple devices (if there are any sensible options?)

Thanks!