At the beginning of the summer, Shopify announced many updates again, along with 10 new free templates. The default theme has changed from Dawn to Horizon, meaning that when creating a new store, Horizon is now installed by default in the e-store.
10 new themes
All 10 new themes are copies of Horizon in terms of code, meaning the code base is very similar, but with its own nuances.
New themes:
The main difference between Dawn vs Horizon
The most significant difference and innovation is related to the management of theme sections and blocks. While Dawn already allows the e-store manager to manage sections and blocks as a no-code solution, in Horizon themes, the merchant can also change general UI settings on a block-by-block basis.

Should I switch to a new theme now?
Only if you plan to change the user interface of your e-shop anyway. if you are happy with the current e-shop theme and its features, then there is no reason to switch to a new theme. Of course, you can install the new theme in your e-shop and play with it a bit without making it public, since it is a free theme.