i would say that isolation daemon layer is always slow down everything inside when need anythyng from outside but my observation is that inside to inside has also not so good performace so this was the turning point why i do not want to use DBs and phpmyadmin inside (consumes resources and its not needed) - in my case its subejectivelly ~ 50% slow down for all in one solution - after some tests i would say that DBs and PHP exacution was very ‘unsatisfied’ and i would be happy with 50% slow down - but i am not goin to measure it .. i do not have yet the docker solution i would consider to use - maybe then i will try performace - which is not my target - target is to have multiple isolated independent WPs - to have full controll about it
try gsearch keyword “docker database php performace” - i only remember one tester who did the SQL reading and then writing performace with php - he achiaved ~ 50% slow down database access
BTW in this forum ater quick search I found this about dosker slow down