What logic are you referring to? Smartsheet forms does provide logic. I'm not using Smartsheet Gov, but I can't imagine it would exist for basic Smartsheet accounts, but not Gov.
https://us.v-cdn.net/6031209/uploads/G65JDN2A2Y16/image.png
When editing your form, on the right side, it defaults to "Field". But you can switch over to "Logic" and click add Logic. I utilize this functionality quite often with forms.
Is there something specific within this functionality that is missing for your purposes?