Intermittent starting problem

My car dint start ,took to the mechanic ,said battery issue…changed battery…came back home…started again…same issue…took to mechanic again…said starter problem…changed starter…same issue…tried 3 different starter same issue…changed brand of starter…worked for 2 days…again same issue…only now…it does not happen every time i start…there is a grinding noise when it starts…try 2 or 3 times…it works…after struggling to… start…need help

i am having the same problem! sort of…sluggish starting getting sluggisher and sluggisher (what, it’s a word!). any clues?