actually ppl with fibre would had prefer fibre if possible.
5G router when now 5G not even popularized, u can look for yes so called "5G fibre" with contract can get 5G router for fibre. 5G is all under DNB, so I would think that all telco also similar performance. Any sifu can correct me if I am wrong
If 4g best ones can look for huawei B618 and B818 they have quite some discussion on lowyat here