Better strategy for dual plans with MVNOs, choose one from Bucket 1 and then add another one from Bucket 2 but from different network. And of course you can select from Bucket 1.1 and 1.2 (dual 5G plans).
I tend to recommend eight and SIMBA as the prefer choice from Bucket 2 because of the free roaming voice but you may not need free roaming voice.
Bucket 1: 5G networks but not including SIMBA
B1.1) ST MVNO 5G plans, like Gomo, CMLink or Zym
B1.2) M1/StarHub MVNO 5G plans, like Maxx and eight
2. Bucket 2: 4G network and SIMBA (SIMBA 5G is more comparable to other telcos' 4G)
B2.1) ST MVNO 4G plans, like Gomo, CMLink or Zym
B2.2) M1 MVNO 4G plans, like Maxx
B2.3) StarHub MVNO 4G plans, like eight
B2.4) SIMBA