It can mean trouble emptying or constipation, it can mean diarrhea, but both only in extreme cases. Motility issues can slow down or speed up the movement of stool in a trouble area. It depends where it is and how much of it there is. It's also known as lead piping and visible through various xrays (
radiopaedia.org/articles/lead-pipe-sign) I'm sure what you have is mild, and not enough to be a lot of worry.
I can guarantee you that everyone with uc has permanent histological changes within their biopsies (irregular vascular blood vessel pattern, anomalies within our colon cell structure, wall thickening, crypt abscesses, and other things). It's how they can confirm we have uc. Having chronic inflammation issues creates an, at-times, hostile environment for our cells to develop in. And as a consequence they look different and have marked structutal changed that are an adaptation to their environment.
Do they impact our quality of life? Generally no. The only histological findings we are concerned about
are those that indicate active ulcerative colitis or dysplasia (pre-cancerous cells) and it doesn't sound like you have either.