I looked into this. The compatibility matrix for it is problematic. Most things these days support IKEv2, but the Synology software doesn't. Android 12 dropped support for L2TP and only supports IKEv2. OpenVPN is just ... bad. The UI is bad; the configuration is bad.

I was going to set it up on SRM, rather than DSM, but the risk involved in messing around with it in a house full of people also using the internet made me pause.

I'm planning on port-forwarding to a Wireguard instance (possibly on an RPi4) instead.

I am considering using it for point-to-point VPN to my mother's house, though (once I've switched out her default router for a Synology one).