Migrating to OpenVPN

For TL;'DR version goto QUESTION;

Hi guys.
After having an AWS server instance running for about 2 years now, I decided it was time to buy a domain name and setup a website.
What I have been using it for up until now was running a VPN server and an Nginx reverse proxy. Basically, I have a pair of robots with a web interface, but their internet connect is via cellphone so the ports are locked-down by the ISP. In order to access the web interface remotely, I connect them to the VPN server and use the Nginx reverse proxy.
Up until now, I’ve been using SoftEther VPN server and it has served me relatively well, but the project is a bit stale and I have security concerns now that I’m not on the ‘darkweb’ so I’ve decided to make the switch to OpenVPN.

I have OpenVPN set up and running, and it works in the same capacity that my previous VPN software did, and now I have different certs for each client, so I feel a lot more secure.

QUESTION: I’m aware of the ability to force-redirect client webtraffic through the VPN by uncommenting: push "redirect-gateway def1 bypass-dhcp"
I have not done this because that would send way too much traffic through the VPN and my AWS bill would be astronomical. But I do want to send my phone’s traffic through the VPN to avoid tracking. Does anyone know how to selectively decide on the client-side whether to send all your traffic through the vpn. I’m using OpenVPN connect on Android. I’m guessing what I’m looking for is on the ‘add proxy’ menu in the app, but I’m not sure how to set it up/whether I need to implement any proxy software on my AWS machine

i think you can edit the client config profile. so issue the config for the client and then add the redirect force part to only that client’s config. also have separate certificates for each client. even if they are all by one user.