Long as you have Ericsson as the sole 5G vendor, don't expect it will improve any time soon at least in the next few years

The gwailo's 5G is said to be far behind Huawei 5G by as much as 3-4 years.

Good luck DNB as users are suckers.

That's still no exact timeline yet. So depends on whether you really need a new phone or not. For now I'll definitely get 5g phone that supports current 5g network first (that officially available in Malaysia, not imported). All of 5g ready phones since 2020 should have support for SA network and NSA network. Therefore that's no need to wait for second network.

The answer is, if you need to buy a new phone now, just get a 5g capable phone. Nobody knows how many years more to wait for second 5g nationwide.
It is not necessary to buy a new phone just for the sake of using 5g.

We can only hope that the second network is 5G SA.
For people who care about using 5g SA in few years to come, they would just buy a new phone again. People who use their phone for as long as it can last probably won't care about 5G SA, because current 5G NSA is more than sufficient.