How much are you getting out with each flush? Two gallons-ish hopefully? Might speed things up by draining the engine block too if you're not getting a couple gallons each time. Capacity is 8.5-9.5 qts
Pics are gone, but the write ups may still be helpful idk:
Coolant Flush
https://www.toyota-4runner.org/1101715-post35.html
Radiator Replacement
https://www.toyota-4runner.org/1034524-post23.html