This is a rather frustrating achievement for new players as it requires not only knowledge as to the locations of health packs around the map but also careful planning of fights to ensure survival and the ability to escape. The best hero to use for this achievement would be Roadhog as his ‘Take a Breather’ ability increases the healing he gains by 50% for 2.5 seconds after usage (as of 14/08/2023).
For memorization of health pack locations I would recommend either starting a private custom game to investigate the maps or using this website:
https://overwatch.statbanana.com/ ;for top down views of clearly marked in game maps (bear in mind this site was made for overwatch 1 so certain maps displayed are no longer in circulation).