Reporting back here for the benefit of everyone. I have just replaced the physical SIM card this morning with eSIM and kept all my other 3 existing multiSIMs. The Maxis representative who helped me with my request said I'm allowed the maximum of 5 multiSIMs, unchanged from what was previously known. Upon activation of eSIM, only the primary multiSIM on my phone got deactivated. The Maxis center I went to was Menara Maxis in KLCC. Hope this helps.