If you have trust issue, You could self host.
There are two flavor of bostr.
https://github.com/Yonle/bostr (NodeJS) (Suited for public/private use)
https://github.com/Yonle/bostr2 (Go Lang) (Suited for public/private use, but require the need of VPN like tailscale/zerotier/wireshark/openvpn for private use only)