Linux-Linux-MacOS file sync?

Question

linux

Good day!
There was a need to synchronize a folder (or several) over the network between Linux servers, as well as MacOS.
SCP, of course, is a handy thing, but sometimes you have to copy several files with a difference of 5-10 minutes. Small files (!).
In short, I'm looking for a multi-platform analogue of GDrive.
Tasks:
1) Created a file on the server, threw it into a folder - hid the terminal, opened Finder - opened the file in the application or copied it somewhere else. Same thing in reverse.
2) I created a file on one server, put it in a folder, took it on the second server
3) Ideally, on MacOS you could connect this folder a la FTP (it is then displayed below) so that it "strikes the eye".
The options with rsync and incron are not very suitable, because in addition to servers, there are also Macs.
Googled a few solutions myself, but they only cover part of the tasks
1) csync2 is a server-only
solution 2) syncthing is a nice enough solution. But I would not want to mess around a lot with the settings and "sawing for myself." In addition, there is no client on macos, as far as I understand. And installing the core version on mac and connecting another server to it is a bit of a crutch.
In an ideal also that the decision was safe enough. So that you can transfer ssh / openvpn keys and other important information through this channel without fear.
Thanks in advance for your replies.
PS There was an idea to raise a vpn network, and in it - smb or nfs. Or is it already too much?)
UPD. I will choose between syncthing and vpn network. The first is because you can set up an isolated system, without the participation of third-party servers. The second - for the same thing, plus the subtleties of settings and the level of security of the level that you wish.
Thank you all for your participation.

Answer 1

Syncthing for Macs is https://syncthing.net/dl or am I wrong ??
don't like sync - take Resilio sync (previously known as bittorrent sync) - a commercial product, with a limited (no more than 10 dirs, file exclusions disabled) free version.

Answer 2

yadisk\dropbox + encfs and a lot of problems solved?)

Answer 3

PS There was an idea to raise a vpn network, and in it - smb or nfs. Or is it overkill?)
This idea has a lot of advantages. not only nfs/smb.. good, right thought, that's how it is for me (Linux + Mac park)

Answer 4

I will duplicate it in the answers. Come in handy.
UPD. I will choose between syncthing and vpn network. The first is because you can set up an isolated system, without the participation of third-party servers. The second - for the same thing, plus the subtleties of settings and the level of security of the level that you wish.
Thank you all for your participation.

Answer 5

1) csync2 is a server-only solution

from what? Mac is Unix-like. but that's not the problem here, csync2 will work on a large number of files because it has a base in sqlite. Try lsyncd
or owncloud or nextcloud