Adjustment of Status - I-485

guys i have applied for i485 adjustment of status and waiting for them to schedule an interview , i would like to post my timeline , any body can share there experience and help me also if somedody is in the same situation , my questions would be
1. after rfe how much more time they will take to respond .
2. can be the i485 application be denied for some reason if yes why ?
3.i have my combo card with me for traveling and EAD , but my lawyer i should not be traveling until i get my green card and he doesnt know when is i am gonna get my GC. so why would he not let me travel , if i have my legal rights to back to country for some reason .
i am posting my timeline for i485 please help and expess you feelings and share your expereince it will motivate me and help me alot .
10/14/2019 application recieved
11/06/2019 accepted finger print , NAtional benefits centre is working on your case .
12/02/2019 finger prints were taken
04/28/2020 RFE
05/21/2020 recieved response to RFE USCIS has begun working on your case .
after that i have not been reciecving any notices or updates from uscis .
whats going on i have no clue HELP !