There is a free and open-source extension that supports display multiple custom shipping methods: "MatrixRate Table Rate Shipping".  
It is compatible with Magento version >= 2.3 and available on both Magento marketplace and Github. The code in Github is more up-to-date than version on Magento Marketplace.

You can use this extension or if you want to build your own module and you can investigate how they build the features.

Link extension on Magento Marketplace: https://marketplace.magento.com/webshopapps-module-matrixrate.html

Link extension on Magento Marketplace: https://github.com/webshopapps/module-matrixrate