TLC in the SATA space has really reached the level where you're not going to see much difference between it and older MLC drives. SATA genuinely is the bottleneck, whether it's still ubiquitous or not. There are still really high performance SATA SSDs out there, but you won't see many of those options in the consumer space because the real outliers that extract the last ounce of performance from SATA, such as Power Loss Protection that allows an SSD to acknowledge data before it's written is relegated to Enterprise options that consumers tend not to want to pay for (consumer SSDs segments is still a race to the bottom, not a race to the top).
Intel for instance just released the D3-S4510 a few months ago. With 3D TLC, Powerloss Protection, and 7.1PB of write endurance, it's more than capable of wringing every last ounce of performance out of the SATA 3 standard. But at $300 for a 1TB drive, most people would be happy just paying half that for a Crucial MX500. Because unless you're running benchmarks for fun all day, it's not going to make any meaningful difference in day to day usage.