Comparison of features of 5G and 6G Network from IEEE
I doubt 6G will be able to provide Tb/sec in sub 6 Ghz spectrum.
Depends on the modulation rate.
Whether it can go for higher modulation rate.
Plus massive MIMO & carrier aggregation.
Even with 1024 or 2056 QAM you will not reach Tb/sec.
Maybe NOMA will help that is more RE squeezed inside bandwidth.
4G was supposed to provide 1Gbps.
Academics always set impossible targets for technology only to achieve 10% of that in reality.