Controller server parameters for an omnidirectional robot

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Hello,

I have a mecanum robot that's using Nav2. Right now, I'm using 2D Goal Pose to move the robot around the map. I currently have two main problems:

1. I can't seem to increase the velocity and
2. It tends to move diagonally (positive x and y and at a 45º angle) whenever there are no objects around.

I've played around with many parameters, from costmap height/width to controller frequency, to max_vel, etc.. but I haven't been able to confidently say something like: Increasing this parameter X resulted in velocity increasing, or something similar (other than costmap size matters to velocity). I've also noticed how some changes that I made to increase the speed have made it less nimble and smart when passing through a "track" full of obstacles that I have.

Things I've already tried: Read Navigation Tuning Guide paper, read several git issues/ros answers (most are due to costmap being small or other stuff that doesn't apply). What's the best course of action, is there a god blessed configuration guide I'm missing, or should I just read in depth about the DWB algorithm and everything will make sense? I'm not looking for a step by step, just point me somewhere!

Here's the config file: context: I'm using a Jetson Xavier NX which might explain why parameters such as controller_frequency might be low. The max/min_vel values may also be wild, that's because I haven't seen any difference after changing them, since it never goes over ~0.4 m/s anyways. My current logic is to have a high max_vel of X compared to Y so it prefers to move forward.

controller_server:
  ros__parameters:
    use_sim_time: False
    controller_frequency: 2.0
    min_x_velocity_threshold: 0.001
    min_y_velocity_threshold: 0.001 
    #0.5
    min_theta_velocity_threshold: 0.001
    failure_tolerance: 0.3
    progress_checker_plugin: "progress_checker"
    goal_checker_plugins: ["general_goal_checker"] # "precise_goal_checker"
    controller_plugins: ["FollowPath"]
    # Progress checker parameters
    progress_checker:
      plugin: "nav2_controller::SimpleProgressChecker"
      required_movement_radius: 0.5
      movement_time_allowance: 10.0
    # Goal checker parameters
    #precise_goal_checker:
    #  plugin: "nav2_controller::SimpleGoalChecker"
    #  xy_goal_tolerance: 0.25
    #  yaw_goal_tolerance: 0.25
    #  stateful: True
    general_goal_checker:
      stateful: True
      plugin: "nav2_controller::SimpleGoalChecker"
      xy_goal_tolerance: 0.25
      yaw_goal_tolerance: 0.25
    # DWB parameters
    FollowPath:
      plugin: "nav2_rotation_shim_controller::RotationShimController"
      primary_controller: "dwb_core::DWBLocalPlanner"
      angular_dist_threshold: 0.785
      forward_sampling_distance: 0.5
      rotate_to_heading_angular_vel: 0.8
      max_angular_accel: 1.0
      simulate_ahead_time: 1.0
      debug_trajectory_details: True
      min_vel_x: -1.
      min_vel_y: -0.2
      max_vel_x: 1.5
      max_vel_y: 0.2
      max_vel_theta: 0.4
      min_speed_xy: -1.5
      max_speed_xy: 1.5
      min_speed_theta: -0.4
      # Add high threshold velocity for turtlebot 3 issue.
      # https://github.com/ROBOTIS-GIT/turtlebot3_simulations/issues/75
      acc_lim_x: 0.5
      acc_lim_y: 0.5
      acc_lim_theta: 0.2
      decel_lim_x: -0.5
      decel_lim_y: -0.5
      decel_lim_theta: -1.0
      vx_samples: 15
      vy_samples: 15
      vtheta_samples: 20
      sim_time: 3.0 #1.7
      linear_granularity: 0.05
      angular_granularity: 0.025
      transform_tolerance: 0.2
      xy_goal_tolerance: 0.25
      trans_stopped_velocity: 0.25
      short_circuit_trajectory_evaluation: True
      stateful: True
      critics: ["RotateToGoal", "Oscillation", "BaseObstacle", "GoalAlign", "PathAlign", "PathDist", "GoalDist", "ObstacleFootprintCritic", "Twirling"]
      BaseObstacle.scale: 0.02
      PathAlign.scale: 32.0
      PathAlign.forward_point_distance: 0.1
      GoalAlign.scale: 24.0
      GoalAlign.forward_point_distance: 0.1
      PathDist.scale ...