How are you emulating an IR remote on a raspi? I dropped down to Rust and gave the thread max priority in Linux but still couldn't toggle the port fast enough

How are you emulating an IR remote on a raspi? I dropped down to Rust and gave the thread max priority in Linux but still couldn't toggle the port fast enough (the remote outputs square waves where the signal for the same button varies by low hundred of microseconds. The frequency changed rapidly enough that I can't use the rpi's built-in pwm). It seemed I'd need a dedicated board running something more embedded-y the rpi communicates with. Instead, I'm going to try to solder transistors to the capacitive buttons on the existing remote and re-use it's board. Unfortunately I can't get replacement remotes and I'm just learning how to solder, so I'm not confident in success.