java.lang.NoSuchMethodError: sun.security.util.ManifestEntryVerifier.<init>(Ljava/util/jar/Manifest;)V
You will need an older Java 8 build
https://www.azul.com/downloads/?version=java-8-lts&os=windows&architecture=x86-64-bit&package=jre&show-old-builds=true
Scroll down to 8u302b08 and install this build
Then open your start.bat and use:
"C:\Program Files\Zulu\zulu-8-jre\bin\javaw.exe" -Xmx4096M -jar forge-1.16.5-36.1.0.jar
pause
There is an issue with lootr
Try an older build:
https://www.curseforge.com/minecraft/mc-mods/lootr/files/5166263
If the issue persists, backup the world and remove this mod
Join the world again - if there is no issue, put the mod back in
Does it work without Optifine? If yes, replace it with Embeddium/Oculus
https://www.curseforge.com/minecraft/mc-mods/embeddium
https://www.curseforge.com/minecraft/mc-mods/oculus