let me tell u what happened. I was like you, using 4G all these while with digi. I said to myself, 4g is good enough for my usage. Then after they rolled out 5G, the 4G "somehow" become like shit. same location indoor same telco, i speedtest with my friend beside, my 4G phone get 0.2mbps, and his 5G get 300-400mbps. I think you can stay back on digi plan, just get a 5G phone. AND, using 4G in a 5G phone can get more bandwidth than a just a 4G phone.

And not to forget, after changing a 5G phone, i need to change my cheapo digi plan to a 5G available plan ( more expensive). Maybe this is the way they earn by making people embark on a 5G plan.

I thought 5G access is only from DNB tower.
4G data is only accessible from respective telco tower.
Maybe I am not as updated as you are.