Coming back to this..
I kinda regret buying the T420 now tbh.. If I knew about the buzzing beforehand, I would've bought the T3A instead (plus apparently the buzzing there is fixable) and it would cost alot less..
Also; I got the left cradle now, and with both cradles and handles (left T210, right T245) connected, the buzzing is worse.
For me and for almost every type of system, a teroidal transformer is much better than a switched one.
The ones I have do not make noise but they must be very well secured and insulated with a large rubber washer where it is attached, this prevents or minimizes vibrations.
But what happens to you is that if you demand more power, it will make more noise.
But if it makes a lot of noise or is bad or is a T410 or a T405 with a T420 label, it only changes the power it delivers, which is about 100w for one and 75w or less for the other.
It is only known from the weight of 4,406kg that of 200w and 400w peak the largest is the T420D.
But only if it is a lot of noise would I complain.
In the end I haven't bought it, customs is a hassle. I prefer to buy another way, that the shipping is from the EU (some sellers do it for a small amount) or that the taxes are included in the price or buying a cheaper one like the T3A Although I don't like the switched power supply, this way I avoid customs problems.
Sometimes they did not send the documentation and it was chaos, I had to go to customs to solve it and it was not easy to get the documentation, in the end I paid double the price of the item.
There is my fear, I don't know why AliExpress eliminates taxes on items over €150.
If anyone knows a seller who sent it in another way, let me know, I would appreciate it and in the end I was going to buy the T420D because I don't like the limitations, in your case if you add a Nas handle and one more support, you spend the same as a complete set of the T420D with two handles.