The "value" key should take precedence regardless of the score, but why does the score show up more?  For example, given the following score.

/scoreboard objectives add TEST dummy
/scoreboard players set @p TEST 1

The following will result in a score of "1".

I really want "hello" to be displayed.

/tellraw @a {"score":{"name":"@p","objective":"TEST","value":"hello"}}
/title @a title {"score":{"name":"@p","objective":"TEST","value":"hello"}}

The wiki says it can be used.

Raw JSON text format – Minecraft Wiki (fandom.com)

Please make the "value" key available.

I wrote this using a translation software, so the text may be a little bit sloppy. I am sorry.

Best regards.