Okay, so far the trend is clearly positive towards installing the 60x60 tiles yourself! Are there also opposing voices or even more in favor?
I'll put it this way: I was young, had a screed floor with leveling compound, unfortunately with slight waves, but still started working with 30x30 tiles in our main room of about 50 sqm in the townhouse. The walls were completely out of alignment, so I laid out the tiles dry beforehand and had to correct the line several times. Overall, I had 10 meters in length and about 5.50 in width. My husband was the assistant with the adhesive, I was the meticulous craftswoman... in the end, we managed it, and afterwards I had to deal with a slipped disc. Therefore, your parameters are cellar rooms: Go for it! However, I would not choose the cheapest option, because they often tend not to be easy to maintain. My experience. I probably would also not recommend the 60 cm edge length. If there should actually be any disruptive factor, you are more flexible with a smaller format. But I guess that's more pragmatic: why make more work for yourself if it can be done easier? [[The question you should ask yourself is, why do they have to be tiles? Do you have an external access there? Of course, tile is a robust surface (in my opinion the best surface for the ground floor because you are constantly going in and out... terrace and entrance), usually a cellar without direct access is not frequented enough that maybe cheaper design flooring would simply be easier?]]