Welcome to the forum
@SV_IdleHour . Congratulations on your seamanship line splicing skills. As any seaman knows line is great but it needs attention. With a lifeline that serves a safety function, replacement and service is part of the mission.
Good suggestions here. Chafe and UV deterioration is going to happen with exposed dyneema line. You’ll just have to expect replacement sooner than if it is stainless wire. If like most boats with plastic coated wire the lifelines should have been replaced several years ago, when the first cracks in the plastic coating started to appear.
While the Line costs will be some what less, be sure to get the termination fittings that cost more. They have smooth radius ends to take the lock spliced end loops of dyneema. While dyneema is tough it does not favor tight sharp bends.
For lifelines in salt water environment I favored bare stainless wire for overall cost and serviceability. I used dyneema for the gates. Great feel and the gate hangs easily with just 2 of the special fittings.
With your splicing skills you can now make your own super strong soft shackles.
One last thought. Have you checked the alignment of the stanchions? Could a well meaning dock worker trying to fend your boat off as it approached the slip, used the stanchion to stop the boat from crashing? They may need to be straightened to get them back aligned and off the side shrouds.