Is --msg-level a candiate for list option syntax?

Currently, --msg-level can only be set like this:

msg-level=all=warn,autoload=warn,cat_ntap=trace

IMO, it would be more ergonomic to set it using the list option syntax, like this:

msg-level=all=warn
msg-levels-append=autoload=warn
msg-levels-append=cat_ntap=trace

It might add confusion, however, the ordering of module/level pairs in --msg-level already matters (e.g. in msg-level=cat_watch_history=trace,all=fatal, cat_watch_history=trace is overridden by all=fatal) and this is already stated in the manual:

Key/value list options
A key/value list is a list of key/value string pairs. In programming languages, this type of data structure is often called a map or a dictionary. The order normally does not matter, although in some cases the order might matter.

Is there a reason why --msg-level doesn't support this syntax? Has it simply never been added? If this is the only barrier, I don't mind submitting a pull request with this functionality.

Start with the manual entries for --msg-level and list options, then trace the existing --msg-level option parsing in the mpv source. Confirm whether repeated list-style assignments can be supported without changing the documented ordering behavior; done means the proposed syntax works and its precedence is clear.