So, in the advanced tab of VIpro's advanced view (the little tab right by edit and stretch) you will have an option for "Start Offset Mode." Try selecting "leg" in that menu, and then fiddle with the "Start Offset" ms and the "Start Offset Attack" ms.
The "Start" fader located by the "attack" fader can then be used to control how much of that "Start Offset" effects the legato transition between notes.
With the right settings, and each instrument/passage is different, you can remove that "harsh" or unmusical transition from note to note.
A number of users make multiple legato patches out of the stock legato articulation for each instrument... and each one may have a different Start Offset Mode to be triggered from repetations, the first note only, or even all.
Also by having multiple edited legato patches, different tuning/humanize settings will also help the performance "glide" from note to note in a much more convincing way.
I would begin your experiments with a string portamento, as it is the most obvious to hear when messing with the Start Offset.
Lastly, if you have an adagio passage of whole notes, save yourself the time and energy and do NOT use the legato articulations.... use the sustains and mess with attack/release.
2019 MacBook Pro, 8 core i9, 32gb RAM. Heavy Digital Audio PC slave, 6 core Xeon E5-1650, 128gb RAM. Logic 10.6.3. Big Sur & Windows 10.