Peaks are high points on the graph, dips are low points. If a frequency has a peak it will play louder then the rest of the frequencies, and of course if it has a dip it will play quieter. This means for example on your graph that a note around 95Hz will sound about 15dB louder then a note of 85Hz. 15dB is an obvious difference. That's why we want a smooth frequency response (FR), especially in the bass region.
Phase is a complicated business and I don't pretend to understand it fully. What I will say is that I made no attempt to alter the phase as I don't have the tools but it does become smoother as you improve the FR.
An attempt to explain phase for music:
https://www.uaudio.com/blog/understanding-audio-phase
This is what REW says about the phase graphs.
https://www.roomeqwizard.com/help/help_en-GB/html/graph_splphase.html
Here's a view of your phase 'unwrapped':
View attachment 151109
Actually yours looks pretty good. In simple terms the less dotted lines you see (in the 'wrapped' graph) the smoother the phase is. Most people find smoother phase sounds better. Here are my phase diagrams for before and after room treatment.
View attachment 151107
View attachment 151108
As the FR gets smoother so does the phase.
The issue for us listeners is that bass wavelengths are similar to our room size - for example 100Hz as a wavelength of 3.43 metres. Because of this it is more difficult to get bass right in a normal sized listening room. That's why when you listen to bass and walk around your room it will sound different in different locations. Our aim is get the bass sound as smooth as possible at the listening position.