I followed this thread and created some scripts that work for a fresh install of ubuntu 22.04.

I couldn't figure out how to get awk's match function to work, so I just used code from @meuh and @JinnKo to create a non-awk version that disables/toggles multiple devices given a keyword.

First, make sure evtest is installed:

sudo apt install evtest

I have two files, one that toggles the touchscreen on and off, and one that always disables it when booting up.

Toggle Touchscreen:

#!/bin/bash

# This toggles my touchscreen

#search for "Touchscreen" or something like that in /proc/bus/input/devices to make sure you're disabling what you want to disable.



path_for_temp_files="/ANY_PATH_YOU_WANT_TO_STORE_SOME_PID_FILES/"

regex='event([0-9]+)'

DEVICE="Touchscreen"



if [ -r "${path_for_temp_files}touchscreen-evtest0.pid" ]; then

    kill_these_files=("${path_for_temp_files}"touchscreen-evtest*)



    for i in "${kill_these_files[@]}"; do

        echo "kill" $(cat "${i}")

        sudo kill $(cat "${i}")

        sudo rm "${i}"

    done  



else

    filename='/proc/bus/input/devices'

    inside=0

    events=()

    while read line; do

        if [[ $line =~ $DEVICE ]]; then 

            inside=1

        fi



        if [[ $line =~ $regex ]]; then

            if [[ "$inside" -eq 1 ]]; then

                events+=("${BASH_REMATCH[1]}")

            fi

            inside=0

        fi

    done < $filename

    

    numevents=${#events[@]}

    

    for (( i=0; i<${numevents}; i++ )); do

        sudo evtest --grab "/dev/input/event${events[$i]}" > /dev/null &

        pid=$!

        echo $pid > "${path_for_temp_files}touchscreen-evtest${i}.pid"

        echo "/dev/input/event${events[$i]} running on pid ${pid}"

    done

fi

Disable Touchscreen to run at boot:

#!/bin/bash

# This disables my touchscreen

#search for "Touchscreen" or something like that in /proc/bus/input/devices to make sure you're disabling what you want to disable.



path_for_temp_files="/ANY_PATH_YOU_WANT_TO_STORE_SOME_PID_FILES/"

regex='event([0-9]+)'

DEVICE="Touchscreen"



if [ -r "${path_for_temp_files}touchscreen-evtest0.pid" ]; then

    kill_these_files=("${path_for_temp_files}"touchscreen-evtest*)



    for i in "${kill_these_files[@]}"; do

        echo "kill" $(cat "${i}")

        sudo kill $(cat "${i}")

        sudo rm "${i}"

    done  



fi



filename='/proc/bus/input/devices'

inside=0

events=()

while read line; do

    if [[ $line =~ $DEVICE ]]; then 

        inside=1

    fi



    if [[ $line =~ $regex ]]; then

        if [[ "$inside" -eq 1 ]]; then

            events+=("${BASH_REMATCH[1]}")

        fi

        inside=0

    fi

done < $filename



numevents=${#events[@]}



for (( i=0; i<${numevents}; i++ )); do

    sudo evtest --grab "/dev/input/event${events[$i]}" > /dev/null &

    pid=$!

    echo $pid > "${path_for_temp_files}touchscreen-evtest${i}.pid"

    echo "/dev/input/event${events[$i]} running on pid ${pid}"

done

Then I followed this answer to run as root at startup