There are a number of ways to achieve this but they can get somewhat complex for a forum explanation. I have a few tips though.
Make your diffuse texture larger and have it contain more of the pattern. Your's shows about 3 or each color. Have the diffuse texture contain 12, 15 or 20 of each color. In that, make very subtle color changes to each value. Then when it tiles you'll have some variation. If you zoom out though, you'll probably start to see a pattern again. It's really hard to control that. But you can make 4 or 5 of these 20-each textures and have each of them be slightly varied. If you have 5 slightly different textures, you now have 100 colors wide sections before the pattern repeats.
Sometimes judicious use of 'Depth of Field' is helpful. Pull the close-up foreground people out and have that area slightly out of focus or soft. Let the focus catch up as you approach the building. Be subtle so you don't get the "miniature" effect. Real cameras generally have some depth of field depending on the lens focal length and f-stop. Think like a lens.
Also, search for parametric tutorials for Parquet floors. You have that kind of thing going, it's just not rectangular units. There are Max tutorials that will show you how to build a parametric Parquet floor that pulls in random segments that tile. It's tedious but it works. Google it.
Rail Clone is great at this. It's not too expensive. If this is a budgeted job, maybe buying Rail Clone will solve it, and you can use it for future similar work. Rail Clone would probably give you exactly what you want.
Rob Holmes

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3ds Max (2023-2025), V-Ray 6.2, Ryzen 9 3950-X Processor, DDR 4 128MB, Gigabyte Aorus X570 Master motherboard, Sabrent Rocket NVMe 4.0 M.2 drives, NVidia RTX 4090, Space Pilot Pro, Windows 11 Pro x64, Tri-Monitor, Cintiq 13HD, Windows 11 x64
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