Unstable Cellular Service iPhone 13 (Maxis)

I'm currently experiencing cellular data connectivity problem with my iPhone 13 using a Maxis SIM card. After skimming through the forums to look for anyone who is facing the similar problem, I found an ongoing post where users are experiencing the identical problem. The only difference is that they are iPhone 11 users.

Link to the said discussion:

https://discussions.apple.com/thread/254853733?sortBy=best

Brief description of my problem:

It all started several weeks ago where the connectivity indicator kept on transitioning from "Edge" and "GPRS". Thinking it was a network outage, I reported to Maxis, but I was told there was no such downtime.

Inserting other telcos' SIM card resolve the problem, there was no connectivity problem. So is the case when I inserted the Maxis SIM card to my Android devices. When I insert my family members' Maxis SIM card, the issue persists again.

Went to apple authorised service centre, they ran the software diagnostics no problem was found. Maxis did their part to reset my network on their end, but still the issue persists.

I would like to know whether is this an isolated case that I'm just experiencing, or is anyone having the same problem too? If anyone out there have similar problem and solve it, pls share your thoughts. I would like to know whether is this a hardware problem or not? I've seen some user mentioning the network IC chip.

I don't really wish to switch telco only to realise that it is a hardware problem