I tbh don't realy know a lot about the ind eph of mods so I don't how to fix it needing javafml:30

Please fill the whole bug issue template. With these information I cannot help you.
It seems you have installed a forge version older than 1.15.1 but you are trying to use the mod that requires 1.15.1 forge.

As there is no response I close this issue. Please reopen with the issue still apears.