Timeless set by DGT - does the design vary

i was watching the Magnus documentary and was checking out the timeless pieces

has the design gone through any changes over the years

would a DGT timeless set bought today be the same design as what was used 10-15yrs ago

in major tournaments?

There are subtle differences. I have noticed differences in the sculpting of the Knight's mane. All in one direction. All in one direction at a slightly different angle. Parted into two sections at different angles. Etc. The ball finial on the bishop is flatter in some iterations. The peaks in the Queen's crown. All very subtle. It might be safest to buy them direct from DGT even though this will most likely not get you the best price if you are especially detail oriented. There might be differences in the weight of the chipped pieces (as used in the tournaments) and the non-electronic pieces if this matters to you as well.

even within just the DGT brand

would the timeless set seen in major tournaments from around 2010 be the same set as today?

Tata Steel 2021 used the same Timeless pieces that had been in production since 2009.

The design of the DGT pieces has changed very little. I think the bishops mitre has become more rounded over the years. If I'm not mistaken the HOS Championship series was modelled on the older type bishop. Here are a few older pics of DGT pieces in action.