I strongly recommend you to try the excellent R. Schreier mathlab toolbox to studdy the modulator order.
https://www.mathworks.com/matlabcentral/fileexchange/19
There is no absolute answer, it depends on.
- your specifications
- the available clock (OSR, jitter)
- the power consumption allowed
- knowledge on mismatch-shaping algorithms
- ...
Most of the converter published recently uses CT modulators, but in that case, you need to have a clean clock to avoid designing a switched-cap DAC.
Avoid low order modulator with a low number of bits inside the quantizer, or you will face tone problems (limit cycles)