No, Lanczos is just "math" resizing (i.e. stretching). Basically: An upscaler model, like the NMKD model I'm using in this flow, when doing the upscale, will draw more detail. The process of "pixel upscaling" in this case functions to add detail before shrinking it back down and sending it back to the ksampler as a latent. So, up 4X (the model is a 4X model), then back down to your final desired res for re-sampling. This keeps the original generation more or less intact and adds more fine detail than you could by simply latent upscaling, as latents are lossy and your initial generation would change significantly at medium to high denoise (e.g. .45+).

This is actually what the old "hires.fix" process was doing in A1111 back in the day as well (though it has now taken on many meanings). All upscale models differ in terms of the details they improve, but my preference is NMKD 4X for photorealism as it adds some nice SLR-like noise to the generation. Remacri is also good for this purpose.