Creating custom form fields – Not working

I have been trying to create custom form fields following the example (https://givewp.com/documentation/developers/how-to-create-custom-form-fields/) but new fields are not showing up on the single form. I tried to check the hooks available as indicated in the tutorial, however they seem to be unavailable when i tried to check with Query monitor pluggin. I could see the give_add_email_tags hook to be available for addition as email tags and as expected this seems to work. However none of the other hooks like give_after_donation_levels appear when i checked through Query monitor. Is it conflict with some other pluggin ? I have checked all other setting as well, however nothing seems to make it work.

Please note that I have a local installation on MAMP and really struggling to make this work. Any leads to solve the issue would be greatly appreciated.

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