New user here and would like to introduce my self to everyone here

Me and my fiance are 24 years old.
I have been living in Singapore since I was 12 (Secondary school > Polytechnic > National Service > Working for almost a year). Got my PR in 2008 and in the process of completing my citizenship conversion. (Completed SGJourney, awaiting for further instructions/renouncement of citizenship).
My fiance has been here since 15 > Republic Polytechnic > Working for 4 years now at a respected MNC > Also part time studying in NTU. She has been holding an S-pass for the duration of her work (4 Years).
We are planning to sign the marriage at the ROM by the end of the year.
She would like to take a break from work and focus on her studies and therefore, before we get married(ROM), we would have to apply for the pre marriage long term visit pass assessment (PMLA). After which we will ROM and apply for LTVP.
I would like to request for your kind advice on when she should tender her resignation from her current job as I am concerned that quitting her job will affect her eligibility of getting a LTVP. I am also concerned that the government will see our marriage as one of convenience and would not grant her a LTVP.
She is currently very stressed out with her job and would like to quit as soon as possible but we are worried that her tendering her resignation will affect the LTVP.
Thank you for your kind advice in advance.
I could not find any similar topic but if this question has been answered before please send me the link and my apologies for re-opening the topic.
Thank you!
Ysera