Better to aim for the 4, as I assume it'll take some time to get everything done, the price will come down later on anyway.
I am only looking for people's opinions now
I miss that mojo of old simple games. Never thought latency on modern OSes could be a barrier.
For example, modern television sets have a "gaming" mode because in normal mode they somehow process the video frames to make them look better, in a way that introduces latency.
Someone who works on audio software told me that audio over bluetooth has a very high latency too.
There are several bits that can introduce latency in a system. The OS is the part that software developers can adjust and improve.