Ugdhar

I don't think you can use embeddium and rubidium at the same time, if you remove one does it still give dupe mod error? *edit: also, thanks for fixing the log post, much easier when you can view it in raw format!

This log is so hard to read with the line wrapping. See the FAQ for the proper way to post logs.

Very first search result on google when I search for "minecraft jinryuujrmcore": https://www.curseforge.com/minecraft/mc-mods/jingames-jrmcore

You will need to upload your logs somewhere on the internet, and link to them here. The links you have provided (file://) are for files on your local filesystem, which we cannot access. The FAQ link at the top of the page has information on paste sites you can use to share your logs.

Also, Optifine only works with specific versions of Forge. The optifine downloads page shows which version of forge it is compatible with. In your case, you are using OptiFine_1.20.1_HD_U_I6 which is for Forge 47.2.18, but you are using forge-1.20.1-47.3.1, and I imagine this could potentially be an issue as well.

Try moving your server to a folder that is not OneDrive, see if that helps.

So first suggestion, don't use whatever text box you used to format your forum post, it ends up being hard to read. In regards to capes, I do not believe forge provides any support for making capes, as that is reserved for Mojang/Microsoft special stuff. If I'm wrong, I'm sure someone will chime in and let us know.

Click the Show All Versions button at the bottom, then point at the little i next to Installer, and click the Direct Download link.

Click the Show All Versions button, point at the little i after Installer, and try the Direct Download link.

You would probably have better luck asking on a Fabric forum, not Forge, but you might get lucky and find someone that uses Fabric also.

You shouldn't be extracting the mod .jar, just place it in your mods folder.

Not seeing any crashes in that log

Pretty sure all 1.20.6 builds are beta currently, since there is no recommended release build yet.

You could try using spark (https://www.curseforge.com/minecraft/mc-mods/spark) to see if it gives you any other insight into what is making ticks take too long, perhaps it's a combination of mods. If it's simply the yuushya mod processing that is causing it to hang, the only solution would be removing that mod, or possibly updating/downgrading to a version that doesn't make ticks take too long.

I don't think embeddium and rubidium can be used together. Try removing one of them.

Did it crash before you added mods to the pack? If not, try readding the mods 1-2 at a time testing in between to find the broken/incompatible mod

You install forge into .minecraft, as that is where the game is installed, so all versions are installed there. You set the directory for each actual game instance, under the Installations heading within the launcher. That's where you'd specify the directory for the version you're playing, per Installation/Profile/call it what you will.

That didn't actually attach your project, it just shows a filename. Also, attaching as a compressed file is not the best way to share, you should create a github repository for it, then share the link here. https://www.google.com/search?q=how+to+use+github

On the download page, click the button for "Show all versions", point at the little i next to the Installer link, and use the Direct Download link that pops up. That should let you download it if you have issues with the adfocus thingy.

Post logs as per https://forums.minecraftforge.net/topic/125488-rules-and-frequently-asked-questions-faq/ They may have information that will answer these questions.

I would say try without optifine

Possibly an incompatability between nether structures and blueprints. Give it a try without one or the other. Also I don't think 4GB is very much for a large modpack, but I don't see any out of memory errors in the log.

I'm not seeing any errors in that log, is it incomplete? At the bottom it looks like canary and radium may be incompatible, I see some warnings about skipped mixins.

Looks like that RAM-Compat mod is for Alex's Mobs, which you do not appear to have in your pack. Try removing it.