Why?

I use Blaze and Cave's advancement datapack and I'd like to pass through the advancement messages from there

What and How?

Pass through certain tellraw messages based on customisable parameters based on an OR boolean operator on an array
To: @s @p @A
i.e.
PassTellrawIfDestination: ["@a"]
IgnoreTellrawIfDestination: ["PxlHeart", "%player%", "%permission_admin%"]
(%player% would be a placeholder for any specific player mention)
(%permission_% would be handled by a permissions manager like LuckPerms)

From: @s @p @A
i.e.
PassTellrawIfSender: ["%any%", "%server%"]
IgnoreTellrawIfSender: ["PxlHeart", "%permission_default%"]
(%any% would be a placeholder for any tellraw sender to pass)
(%server% would be a placeholder for if the tellraw came from the server/console)
(%permission_% would be handled by a permissions manager like LuckPerms)

Contains: string
i.e.
PassTellrawIfContains: ["has made the advancement", "has completed the", "%*% has made", "%*% has completed"]
IgnoreTellrawIfContains: ["Hey there! Hope you enjoy the server!", "Everyone welcome %*% to the server!", "task", "Getting Wood"]
(%*% would be a placeholder for a wildcard in terms of a regex lookup)
(Preferable contains wouldn't be case sensitive, though it could be configurable or separate)
i.e.
IgnoreTellrawIfContainsIsCaseSensitive: false
OR
IgnoreTellrawIfContainsCase: ["WoAH HeY YoU Can'T SaY ThAT"]
IgnoreTellrawIfContainsNoCase: ["woah hey you can't say that"]

Preferably the Pass and Ignore won't be exclusive configs.
i.e.
The tellraw gets passed if the player who sent it is PxlHeart (me).
But, if it's going to PxlBrain (a specific player), it gets ignored.
Ignore takes precedence over Pass.

Also preferable if embedding user images are possible and grabbing the hover-over data of the message to get the advancement description.

Are there alternatives?

Allow all tellraws with only a IgnoreTellrawIfContains: [""] config

Or, maybe even (though I doubt even possible, probably far too complicated) link to the datapack to grab advancement trigger data.

Checks

• I have used the search at least once to check if my idea has already been suggested and perhaps already implemented.

Anything else

Nothing.
Feel free to ask for clarification about any specific point, I'm quite bad at explaining things.

That works, thank you!

I'm unsure as to how we would even go about supporting that so will leave for someone who does know, but to answer your original query someone on our team has made a modified version of that datapack which should support DiscordSRV.