Most importantly, the game is intended for a wide audience. It is certainly not a Solasta where it is enough that they sell 100k (even a million) copies and that's enough.
Comparing the game with Solasta also does not make much sense, both games target a different audience.
There was no chance that the D&D balance would hold up against the game, especially if there were concerns that most players would bounce off the system.
The first change was the rest system, in this case from the very beginning there was no chance that it would be as restrictive as on the table.
In a game, it just wouldn't work.
Surprisingly, the earlier system interaction seemed much more sensible to me with automatic short rests but for some reason they changed it (probably WoTC).
When the rest balance disappeared, so did the other systems.
In that case, the fights had to be designed to be more difficult and longer (at this point the changes are too small anyway)
Another change was that Larian thinks too many misses don't work in a video game (Obsidian thought the same thing with PoE so it's not unreasonable).
We can argue whether or not it really would, it doesn't really matter as long as Larian (and WotC) think it won't work.

While the changes in the combat system, such as backstab, advantage or surfaces will probably change, the basic problems will remain, which will make the balance quite different.