Is there a simpler and more elegant way of showing frontmatter for a paper in a nested list

Question

I have been playing with Obsidian and R trying to do some cleaning up of YAML properties on dozens of papers. I have used dplyr, tidyr, purrr, ymlthis to achieve this. Still I am finding some challenges in dealing with nested lists. Here is a case.

Let's say we have a paper with this data (originally in YAML):

li <- list(
    aliases = "Al-Kadem2016",    
    type = "paper",
    title = "Real-Time Estimation of Flow Rate in Dry Gas Wells - A New Field",
    citationKey = "Al-Kadem2016", 
    id = "SPE-182754-MS",
    DOI = "https://doi.org/10.2118/182754-MS",
    ISBN = "",
    volume = "",
    url = "",
    authors = list(
        "Mohammad S. Al-Kadem",
        "Mohammad S. Al Dabbous",
        "Ali S. Al Mashhad",
        "Hassan A. Alsadah",
        "Dhafer Al Shehri"
    ),
    institutions = list(
        '[[Saudi Aramco]]',
        '[[KFUPM]]'
    ),
    published = '2016-04-25',
    conferenceName = "Saudi Arabia Annual Technical Symposium and Exhibition",
    location = "Dammam, Saudi Arabia",
    publisher = "SPE",
    created = '2023-01-26',
    cdow = "Thursday",
    downloaded =  '2023-01-26',
    summary =  "An empirical correlation was developed to calculate the real-time flow rate in dry gas wells at the surface utilizing the most appropriate parameters: upstream flowing wellhead pressure, downstream flowing wellhead pressure, upstream flowing wellhead temperature, and choke size.",
    critique = "Shared with VFM team. Contains **Panhandle choke correlation original and
  modified**. Covers some empirical choke correlations, applicability and limitations.",
    rating = 4,
    pages = 10, 
    references = 5,
    review = "",
    tags = "",
    has_glossary = FALSE,
    cited_by = "",
    up = '[[Choke Correlation]]', 
    down = "",
    related = list(
    '[[Gas Wells]]',
    '[[Atlas/Concepts/Empirical Correlations]]',
    '[[Atlas/Concepts/Flow Rate Estimation]]',
    '[[Atlas/Objects/Venturi Flowmeter]]',
    '[[Atlas/Objects/Plant Information]]'        
            ),
    research = "CHK",
    notes = "what-makes(iiii) + doi + authors + tags(iiii) + snips(iiii) + view + defs(iiiii)",
    cover = '[[poster-20231026193936.png]]',
    poster = '[[poster-20231026193936.png]]',
    pdf_annotated = FALSE,
    zotero_up = FALSE,
    zotero_notes = FALSE,
    zotero_highlights = FALSE,
    uuid = '20230126065407',
    added = '2023-01-01',
    pdf_attached = "spe-000000.pdf",
    pdf_highlights = FALSE
)

li

which yields:

$aliases
[1] "Al-Kadem2016"

$type
[1] "paper"

$title
[1] "Real-Time Estimation of Flow Rate in Dry Gas Wells - A New Field"

$citationKey
[1] "Al-Kadem2016"

$id
[1] "SPE-182754-MS"

$DOI
[1] "https://doi.org/10.2118/182754-MS"
...
...
...
$zotero_highlights
[1] FALSE

$uuid
[1] "20230126065407"

$added
[1] "2023-01-01"

$pdf_attached
[1] "spe-000000.pdf"

$pdf_highlights
[1] FALSE

I have been able to produce this R code to extract keys and values for the paper nested list:

# get values from frontmatter
fm_pluck <- li

for(i in 1:length(fm_pluck)) {
    element  <- fm_pluck[i]
    key      <- names(element)
    values   <- unlist(element)
    n_values <- length(values)
    cat(sprintf("%2d %2d %-15s", i, n_values, key))
    if (n_values > 1) {
        cat("\n")
        for (v in 1:n_values) {
            cat(sprintf("%20d %-12s \n", v, values[v]))    
        }
        
    } else {
        cat(sprintf("%-20s \n", values))
    }
}

which gives me something like this:

1  1 aliases        Al-Kadem2016         
 2  1 type           paper                
 3  1 title          Real-Time Estimation of Flow Rate in Dry Gas Wells - A New Field 
 4  1 citationKey    Al-Kadem2016         
 5  1 id             SPE-182754-MS        
 6  1 DOI            https://doi.org/10.2118/182754-MS 
 7  1 ISBN                                
 8  1 volume                              
 9  1 url                                 
10  5 authors        
                   1 Mohammad S. Al-Kadem 
                   2 Mohammad S. Al Dabbous 
                   3 Ali S. Al Mashhad 
                   4 Hassan A. Alsadah 
                   5 Dhafer Al Shehri 
11  2 institutions   
                   1 [[Saudi Aramco]] 
                   2 [[KFUPM]]    
12  1 published      2016-04-25   
...
...
...       

In other words, I am getting what I want but I find the code lacking; there are two for-loops in there.

I was wondering if anyone could suggest a more efficient and elegant code to print the keys and values on the screen. I am aware of the existence of ymlthis::as_yml(), but it is not about pretty-printing but rather learning traversing techniques in nested lists.