That CNN website is great, except it still has a huge cookie banner. Looking at the cookies of the site, I think the only cookie it sets is that i clicked on the banner. Most of the size of the page is also related to the banner it seems.
This is one of the best, succinct lists of motivations for hybrid warfare i've seen.
But i could suggest another potential benefit for russia:
If russia already operates under the assumption that they are in a (cold) war with EU/NATO, and they don't care about the effects on the relationship with Finland. Then this may simply be a really low cost, high damage operation. That not only imposes the replacement cost of the cable, but also forces countries to invest in counter measures.
How does it solve for time without location? With GPS location and time are one solution to an equation with 4 unknowns (x,y,z,t). Without location you won't know the time delay between you and the transmitter.