Hi Irida, sorry for answering so late.
Buying from Plaisio has some serious drawbacks imo. First of all, they usually charge a high premium for most of the hardware parts, 10-20% more expensive from the average market price, in some cases. Furthermore, they offer a very poor variety of products from each category of hardware. So, at the end you buy less "hardware" for your money, and not always the best you can find at the given price range. You're kind of limited to their narrow list of parts.
Instead of buying the parts and ordering the assembly from the hardware store you'll end up with, I suggest you take a look at a prebuilt system from another pc store (with more flexible builds), and make the changes you want, customizing the build. It's easily done, no worries about that.
Just to give you an example, you could order this one https://www.e-gate.gr/868355/e-gate-amd-swift-gtx-maverick-ryzen-9-3900xt16gb1tb500gbgeforce-gtx1660no-os and ask them to add more RAM, according to your needs, ex. 32(=2x16)gb or 64(=4x16)gb. The same goes for prebuilt systems from other pc stores too. Most pc stores give a 3 year warranty and free support period (each one has its own policy of course, but this can be easily cleared out before the order).
As for the parts, let me start with saying that imo now is the worst time to buy a graphics card. The new 3000 series from Nvidia just came out with an excellent performance boost compared with the previous 2000 series, but with very low availability and a huge demand from users around the world. I'm sure you don't need an RTX 3080 for your workflow, and even a 3070, when it comes out, might be overkill for you too. You should aim at the mid-end category, in my opinion. The new mid range cards, i.e. 3050-3060, should be released in 1-2 months from now. Buying a new 2060 or 2070 today would be a waste of money, because their replacements are around the corner and they will make their performance look obsolete due to the performance/$ improvement. The way I see it, you have two options. Either you buy a used (2nd hand) graphics card at a much lower price (personally, that's what I did a few days ago, buying a 2080 at a very good price), or you buy a low/mid-end card now, like the gtx 1660 in the system above, as an intermediate solution, and upgrade once the new mid-end cards come out later this year. I know, both solutions might not seem too attractive, but believe me, anything else would be a total waste of money in your case. It's up to you to decide.
The cpu now. This is where you should focus, imo. You'll be needing fast rendering times with Vray. If your budget was a bit more flexible, I would definitely suggest the 3950X. It's the best cpu at this price range. Since you include a monitor inside the budget and the actual budget for the tower is further reduced, the next best thing is the 3900XT. It's a very decent and affordable processor, with high STP (single threaded performance, which is paramount for most tasks, like modeling, editing etc) and it's very powerful in rendering too. You can see and compare the rendering performance of various cpus in Vray here https://benchmark.chaosgroup.com/next/cpu?search=
An equivalent from Intel would be the 10900K, but at a significantly higher price (590€ vs 3900XT's 420€ lowest prices at the moment we talk), so for me it's not worth it.
And last, the monitor. Given your budget and use, I would aim at a 27" 1440p IPS monitor. With 3ds max you could have issues with scaling, afaik, so a 27" 4K would be too dense in pixels for you (even though there are some workarounds on that). I personally own a 27" 4K monitor, but since I'm mainly a Blender user and Blender allows for UI scaling at will, I have no issues whatsoever.
You could check these monitors as decent solutions for around 300€:
https://www.skroutz.gr/s/21404653/Dell-P2720D.html
https://www.skroutz.gr/s/24342131/AOC-Q2790PQE.html
https://www.skroutz.gr/s/10500387/BenQ-PD2700Q.html (I own the smaller version of this one, the PD2500Q, as a secondary monitor, and I know for a fact that it's one of the best monitors in this segment of the market, with excellent colors covering 100% of sRGB and Rec. 709, and it comes pre-calibrated from the factory, that's why it's an affordable option for many photographers).
If you want to eventually go for a 4K, check this one out: https://www.skroutz.gr/s/19528409/AOC-U2790PQU.html
I don't know if all this information helped or made things more complicated.