load_variables for zcta or zip code tabulation area

I would like to pull variables and concepts for ACS (5-year estimate) variables specifically for zctas, but am running into challenges.

When running the following command in R, I get 27,850 rows with varying levels of geography (e.g., block groups, tracts) but not zcta's. 

acs5_variables <- load_variables(2020, "acs5", cache = TRUE)

Question: is there a way to pull variables and concepts for zcta's using load_variables or other commands/packages or am I relegated to using online tables such as this one:

Census Data API: /data/2020/acs/acs5/variables?

Thank you,