The main problem with tempo and dynamic variations in baroque music is that baroque music tends to be polyphonic with independent voices and skewed themes. Volume changes cannot be done independently without having the transparency of the polyphony suffering, and tempo changes in mid-strife tend to hit different themes in the voices in different state of progress.
So the main opportunities for significant changes happen at times of resynchronization, like a non-polyphonic chorded passage after a fermata, or a chant passage. Of course the latter mainly applies to singing.
Random changes in tempo or volume are not "musicality". Musicality arrives from organically dealing with music and expression. In polyphonic music, it's about making the individual voices coherent by tieing them together with consistent articulation and phrasing.
With piano music, it can be excellently hard to give one line running through different fingers and hands a distinctive phrasing and dynamic flow separately from other lines. And to keep a level of similarity of the phrasing and dynamics of various themes as they are taken up by different voices.
That's a lot harder and requires a lot more musicality than imposing some irregularities on basically monorhythmic music.