Those are BIG tiles. Large Format Tiles (LFT) are anything with a SINGLE SIDE that is more than 15". Your choice CERTAINLY fits the bill. The tile setter needs to be WELL EDUCATED with this product (ahem...s/he paid for and traveled to the training centre and took the 3 day course).
And the homeowner needs to understand that 1/16" grout lines are probably NOT possible with LFT tiles. The "best practices" will indicate at least 1/8" grout line or bigger is NORMAL for LFT (the installation instructions for the tile will dictate what is ALLOWED).
And IF (big 'if) the smaller grout line is allowed, then SERIOUS subfloor preparation is needed. And by serious I mean EXPENSIVE. As in 'almost the same cost as the tile' type of expensive (per square foot).
Please speak with your designer, the tile EXPERT who will sell you the tiles and then read the INSTALLATION instructions for your chosen tile BEFORE you PURCHASE anything. And Home Depot (or any other big box store) is NOT a 'tile expert'. You will need to purchase these tiles from a high-end store who offer installation 'in-house'.
Grout matching should not be an issue. Using a high-end grout (again it will be DICTATED by the tile manufacturer) that is stain resistant is not a problem. Actually the colour of the grout could be the least of the problems. There could be some real doozies in the future should the wrong installation format be used (small grout lines, improper subfloor prep and improper grout choice).
Please reach out to your local, high-end tile and stone store for more information about your preferred product. Have them COME TO YOUR HOUSE before offering a quote for installation. Only after a walk-through of your space will you get an honest/real quote with appropriate numbers. Do not trust anyone who sells these with a "square foot installed" price. There is no way to know the cost of install without walking through your front door.
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Specifically about rectified concrete look porcelain
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