What about using the .edn format for the properties and metadata?

Prof of concept


With header properties.

#+TITLE: Morning Routine
#+AUTHOR: stindrago
#+DATE: 2022-06-06
#+LANGUAGE: en
#+TAGS: [routine, daily]

to

:title "Morning Routine"
:author "stindrago"
:date "2022-06-06"
:language "en"
:tags ["routine" "daily"]

With block properties.

:PROPERTIES:
:TYPE: book
:AUTHOR: Andy Weir
:RATING: 9/10
:END:

to

{:type "book"
 :author "Andy Weir"
 :rating 9/1}

With < expansion.

#+BEGIN_IMPORTANT
Use tags not folders.
#+END_IMPORTANT

to

{:important
 "Use tags not folders."}

With tasks.

NOW Daily exercise routine at 7am.
SCHEDULED: 
<2022-06-07 Tue 07:00 .+1d>
:LOGBOOK:
CLOCK: [2022-06-07 Tue 07:00]--[2022-06-07 Tue 07:30] =>  0:30
CLOCK: [2021-06-08 Wen 07:05]--[2022-06-08 Wen 07:30] =>  0:25
:END:

to

NOW Daily exercise routine at 7am.
{:scheduled true
 :date "2022-06-07"
 :time "07:00"
 :recur :daily
 :logs [{:start {:date "2022-06-07" :time "07:00"} :end {:date "2022-06-07" :time "07:30"}}
        {:start {:date "2022-06-08" :time "07:05"} :end {:date "2022-06-08" :time "07:30"}}]}

Can it be a good way of writing metadata? The way it displays could be different.