Hello,
At the moment, the only conversion tool available for the public is https://migrationtools.juniper.net/i2j/ and I think it is decommissioned already.
The second tool which you have mentioned - https://partners.juniper.net/partnercenter/sales/jfmc/index.page is only available for partners and Juniper.
If the above two are decommissioned then you can reach out to your Accounts Team to get an alternative. For sure there will be scripts available but I think it is best to get it officially from Juniper.