Septic tank keeps flooding back into the house.

Hey folks! Need an opinion, or even possible solutions here. This has been a persisting issue for years, since home purchase in 2019.

After heavy and persistent raining these past few days here in Georgia, my septic is flooding my downstairs bathroom again. We’ve done many things to help with the issue: we’ve had a brand new drain field installed, the tank serviced multiple times, a dry creek bed installed to catch water on the side of the house, and an irrigation ditch running the length of the back yard to redirect water. We’ve been meaning to install a release valve in case of a backup issue again, so it would release into the yard instead of the house, but the season has been busy and we got lax.

Is my only recourse at this point to install a new, much larger tank? Would adding dirt to my back yard to change the grade help? Maybe it will help with additional dirt for the drain to, well, drain into. Or would the pressure valve be enough?

I’m at my wit’s end at this point. Any advice would be appreciated!