Man, that "probably" is doing a ton of heavy lifting.
People without constant stress have less temptation. In times where my anxiety is the lowest due to sheer circumstance, any reason I have to doomscroll vanishes and I can then occupy my time with a hobby. But it's not because I chose to do away with my phone that I'm able to do so, it's because I didn't have to spend all my time and effort fighting stress. The less stress, the closer the "choice" gets to being a no-brainer, entirely automatic.
Say you decide you're now a chess person. Instead of doomscrolling before bed you find relaxation in the meditative study of chess games for an hour a day before going to bed and now you use your phone only as an alarm. You join your local chess club to play IRL during weekends and attend some classes too. What were the effects? Well, there are the proven long-term cognitive benefits of learning and practicing chess, there's the immediate cognitive and emotional benefit of a larger social circle and a community, and medium term you'll feel good about yourself for achieving milestones (getting to 1000 ELO, winning the weekly tournament, etc.)
None of that would have happened if you had stayed on your phone. You probably already invest just as much time on it as you would in chess in this scenario, but it has no ROI, it is designed to suck you in.
I think "giving you motivation" isn't the right way to frame it, but "probably" isn't doing heavy lifting. More like providing the affordance that wasn't there because the phone took it away and convinced you that you didn't need. Like a typical drug addiction or pretending you don't need to make friends because you have colleagues.
People are spending the amount of extra time on their phone every day that it takes to raise kids, so if you've never figured out how to allocate that time effectively, it's a good place to start.