user_echo_webhook.py

import disnake
from disnake.ext import commands

description = """This is a script wherein the user can input
                 a UserID as well as message content, and the
                 bot will create a webhook to "impersonate"
                 specified user, so to speak."""

intents = (
    disnake.Intents.all()
)  # Not limiting the permissions, since this is an example - set this accordingly.

client = commands.Bot(
    command_prefix=commands.when_mentioned_or("!"), description=description, intents=intents
)


@client.event
async def on_ready():
    print(f"Logged in as {client.user} (ID: {client.user.id})")
    print("------")


@client.command()
@commands.has_permissions(
    administrator=True
)  # To make sure that not everyone can use this command.
async def userecho(ctx, member: disnake.Member, *, content):

    await ctx.message.delete()  # We don't want users to see who initiated the command, to make it more realistic :P

    # We fetch the channel's webhooks.
    channel_webhooks = await ctx.message.channel.webhooks()
    webhook_count = 0

    # We check if the bot's webhook already exists in the channel.
    for webhook in channel_webhooks:
        # We will check if the creator of the webhook is the same as the bot, and if the name is the same.
        if webhook.user.id == client.user.id and webhook.name == "Bot Webhook":
            await webhook.send(
                content=content, username=member.display_name, avatar_url=member.avatar
            )
            return  # The program will not go further.

    # If the webhook does not exist, it will be created.
    new_webhook = await ctx.channel.create_webhook(name="Bot Webhook", reason="Bot Webhook")
    await new_webhook.send(content=content, username=member.display_name, avatar_url=member.avatar)

    # Finally, sending the message via the webhook - the bot will fetch the user's display name and avatar.
    # TO_NOTE: This method cannot impersonate the member's roles, since it works using webhooks.


client.run("YOUR_BOT_TOKEN")