hello,
yea, using the default discord webhook api from roblox doesnt work which is why people recommend using a proxy instead.
there are some good ones out there, ive heard that https://webhook.lewisakura.moe/ is a good option and ive used this one in the past.
keep in mind that these are hosted by other people so they could be malicious, so dont use it for things such as announcements in your server
if you DO want to use it for important things, the best option is to host it yourself. there are many tutorials on how to do this, such as this one.
to use the proxy in your games, you can follow this tutorial and change https://discordapp.com/api/webhooks/ to whatever proxy you are using
good luck!