A few things that have helped me as a fellow "mature" learner:
1. Research the concept of "arm weight" for left hand technique--this is the key to tension-free playing, as Ludwig suggests above.
2. The easiest way to get comfortable with this is first to play seated on a stool, so you can focus on using the arm weight without having to worry about balancing the bass while standing.
3. Research use of "solo" strings. As name suggests, they are designed to be used for solo playing, tuned a step higher than standard (i.e., A, E, B, F#). But they can also be downtuned to play at standard pitch, the result being a lower tension set. Many varieties of strings come in solo versions.
4. At least in my experience, "synthetic" strings with nylon/perlon cores tend to feel less stiff than strings with steel/metal cores.
5. For general inspiration, listen to anything by your namesake, a widely admired Canadian bassist, if you are not already aware of him. Many wonderful recordings in his catalogue.