NateDrake on the ResetEra forums claims that the DLSS-compatible Switch may differ from the upcoming Switch Pro with OLED screen and 4K support, and, due to the ongoing chip shortages, the DLSS version could end up pushed back to 2022. We should be seeing a new Nvidia SoC, though, and the DLSS hardware features will be supported on the handheld SoC rather than the dock SoC.
https://www.notebookcheck.net/New-details-emerge-regarding-the-Nvidia-DLSS-support-on-the-upcoming-Nintendo-Switch-console.527197.0.html