What make operators not keen to provide roaming 5G SA? Cost? Infrastructure not fully setup for country wide 90% and beyond coverage?
You said many operators not happy SG shutdown 5G NSA, maybe can nego for 5G SA roaming with our traffic light telcos for those having 5G SA SIM but should be more expensive for those foreigners operator.
Those cheap roaming data SIM from shopee like ICC, NPM etc their SIM I think very likely is up to 5G NSA only, definitely not a 5G SA SIM.
Even our 5G SA as of now already not provided full SA coverage since most of them drop to 4G since 5G NSA shutdown so idk what is their claim of full coverage standard by IMDA.
so companies will only provide under 2 scenarios: either tio forced to, or they can monetise
5G SA is like a new infrastructure, and roaming on 5G SA requires investment, new billing system etc etc, this will affect from business to finance. european countries mostly do not have 5G SA locally, so they have no incentive to do this for roaming. remember, you need both operators to have this billing system to tally the charges, no point buying this system when you don't even have 5G SA locally... you are essentially paying money to the other operator when your subscribers roam there.
next, roaming sim or travel sim - ICC, NPM, Airalo, Nomad, Eskimo, Firsty and many more, to make things simple, they are actually purchasing sim cards (esim usually) from telcos. And they sell the sim cards to consumers like us. so if these sim cards come from telcos, you can be rest assured there will be no 5G SA roaming. ultimately, infrastructure is still dependent on telcos.