I have Connect version 3.19, but I also observed this in 3.18. It looks like you can now only base new surveys off of feature layers, rather than downloading copies of existing surveys. There used to be an option to browse your organization's surveys but I only see feature services now.
I tried performing a "Save As" on a survey from one of the surveys I found on https://survey123.arcgis.com/, but it said that surveys created in Connect could not be saved that way. Can anyone advise on a new workflow for creating copies of surveys? Has this feature been done away with?