So currently I have a gs500e 2004 model and I acquired the bike back in March, got the carbs synced and all the maintenance done but a week ago my bike hit reserve and note that before that bike was running great no missing at all, after refueling the bike started sputtering, wasn't going above 5k rpm, got home cleared the tank drained the petrol from the carbs, refilled it with high quality petrol, now the bike wasn't even going above 3k rpm, got it loaded and took it to the workshop, cleaned the carbs thoroughly, checked the present petrol, it was clean, cleaned the plugs, cleaned the fuel filter, issue still didn't resolved, I am confused and tired.

bowl gets fuel quick enough? maybe there is debris on the hoses/secondary petcock, you cleaned float seat valves?
check the carbs are getting correct flow