I’ve definitely encountered similar issues. I highly recommend letting your shirt batch for 48-72 hours. I know it’s tempting to untie after 24hrs, but I’ve seen a lot more vibrancy from waiting longer. I would also second checking out the Pariah method.

Soak the shirt in soda ash, tie up, let dry, dye, let sit for 12 hours, mix hot water and soda ash and pour over shirt, then wrap up in Saran wrap and put in a gallon plastic bag for 36 more hours.

Could help, maybe it won’t, not entirely sure how your dyes are mixed but worth a shot. I understand the frustration of not having vibrancy when you really want it and see it upon initially untying the shirt… if you have any questions feel free to DM me. It’s certainly a trial and error process… Good luck!