Your post triggered the anti-spam which hid it from everyone. Please share a *link* to your debug.log and/or crash report on https://paste.ee to avoid this in future so that you don't have to wait so long for help.
Forge version: 49.0.3
Minecraft version: 1.20.4
Note that as this is the start of a new version, it is recommended that you check the downloads page and use the latest version to receive any bug fixes, as the first ever build of Forge for any MC version is usually buggy.
The first build for Forge 1.20.4 has been released! It is based on 49.0.2 for 1.20.3, which reimplemented support for executable server jars and should improve compatibility with slow server hosts.
The reason Forge uses the same major version as 1.20.3 is because the difference between 1.20.3 and 1.20.4 was a single line change by Mojang that fixed a data loss bug. All 1.20.3 mods should work in 1.20.4 and there is no reason to use 1.20.3 which came out a day or two earlier.
If you find any issues, please let us know on the Discord. Sorry for the delay writing this post.
The command you need now in the run.bat is:
java -jar -Djava.net.preferIPv6Addresses=system (forge jar filename).jar
Yep, that's it. You don't need any of those super-long args anymore thanks to the simplified launch system in Forge 1.20.3+.