I manually use a DIY /ping command to check multi-instance status.

@commands.hybrid_command(name="ping", description="ping the server")
async def ping(self, ctx:commands.Context):
    res = "> Ping: Server is on and this instance is active."
    return await ctx.channel.send(res, delete_after=3, silent=True)

btw, I don't see much rate limit.