Closing balance is the most important not less than 500 k but I hope you are not going to transfer big amount just in short period , it will be suspicious. Maybe deposit the money into your account little by little till February till it over 500k . A friend of mine apply through Jakarta embassy and she don’t work but her husband made bank statement movement for her just one month before apply with closing balance over 500k .
My friend got 1 time rejected as he put the wrong date and second time he re apply again the next day and they request more docs and as the same day he got approved . This was happened in Jakarta before in Dec . In your case please recheck the documents and can reapply again .
I think it doesn’t matter and it’s up to you . Nobody come to check if you train or not at the gym . But if you wish to start it later make sure that the gym would be ok . Not sure how the gym issue the paper for you but normally they will be time to start and end on the packages and on invitations letter to embassy would mention when you will start the gym which is not true 🤣