Aight so, I was just messing around with the launcher, and I eventually found out that the reason why the custom launcher isn't working is because of the server list AND authentication of the servers.
if you want to know the reason why both of them aren't working, here are the reasons:
1, The server list - the IPs of the servers are outdated, Apex isn't a thing anymore and the server list is just outdated.
2, the authentication of the servers - now, that we know that the server list is outdated, the launcher itself will only recognize servers that have their protocol (

ip, port, and yes, the slash of the server list.
If you don't get what I am saying, basically, the launcher only will work if you get server ips that have "/soapbox-race-core/Engine.svc" in them, not the usual "/Engine.svc" (and that's what most servers use)
Now, the only 2 servers that are still up and have "/soapbox-race-core/Engine.svc" is: World Evolved RU aka World Evolved V2, and Freeroam Sparkserver, but there's a twist to it: they don't work as I have tried them and they both gave me an error.
Freeroam Sparkserver gave me the message "This server requires launcher with Modern Auth support. Please update your launcher" which gives an outdated sign, doesn't it?
And World Evolved gave me the SSL support error. so this leaves outdated/deprecated signs, but if i ever find a way to update this or get a server that has jlauncher support and "/soapbox-core-race/Engine.svc" in the server ip and getting it to launch and launch the game, then I will make a post about it, and replace this post and making my own post about it.
- VoiD