Do you have any plans to release this mod for version [forge modloader for minecraft 1.21.4]?

I only found versions for neoforge and fabric, on the curseforge and modrinth websites.

Forge versions are low priority and will lag behind regular releases. Depending on if there's any other 1.21-cycle releases, a Forge version may come out early next year. However, I recommend migrating to NeoForge.