@TTerholz
Unfortunately default values for columns like Choice, and Date columns are not carried through to PowerApps, other defaults like text columns and number columns do.
This has been a long time running issue.
All of the Defaults (that you can get to with PowerApps) will be in the Defaults function. This is, in a sense, a "variable" of the defaults for a list.
Example, if you had a number column with a default of 10, then Defaults(yourList).yourNumberColumn would show 10
You can also patch the Defaults to add manual defaults such as this for a Date column where you have SharePoint default set to "Todays date".
Patch(Defaults(yourList), {yourDateColumn: Now()})
This would then have the date column with the current date in it.
I hope this is helpful for you.