According to this rumor, SW2 has the same amount of RAM as the PS4, which isn't very impressive these days. However, I doubt that it can come close to matching the PS4's 176 GB/s of RAM bandwidth, especially considering Nintendo's reputation for being too cost-conscious. What is the maximum RAM bandwidth that the SW2 can achieve? Could it be 52 GB/s using LPDDR5?
The PS4's GCN had lower effective bandwidth due to not having delta color compression. I'd say an Ampere GPU should get similar effective bandwidth to a PS4 if it has ~90-100GB/s raw memory bandwidth assuming the CPU cores aren't more demanding (which they should be).
Regardless, the T239 had better be equipped with at least 128bit LPDDR5 5500MT/s memory for 88GB/s total plus a boosted up amount of L2 cache. If Nintendo stopped at 64bit LPDDR5, then it's going to be very limited in what it can do above 480p.