Honestly, I want to say it's better if you sort it out yourself. "Teach a person to fish..." and all that. The problem is that certain decisions by the devs make it painfully difficult for me to even help you through the process. That's pointed at any devs who may read this, btw, and not you. You don't need to go through those threads.
Do note that the project you asked for is archived and no longer actively developed. I had to actually port it to MUSL libc for it to compile. It may or may not work for you.
To build it it I had to install libopenssl1.1, libnss, and nspr - you may need some or all of these for this to work: https://va1der.ca/~public/openwrt/badvpn_arm32.tgz