I would say mostly. For something of this scale I or anyone else can’t certainly comment until it is tried.
The 2.1 release is pretty close to being done, the problem is some edge cases.
The main bottleneck for performance on 2.1 is the clients which try to work around outdated restrictions like filters active at any time by horrendously batching requests.
A lot more can be done relay side if clients could signal better what they want.