I cut off social media... and stopped smoking

I was and still am kind of an addict of my devices, constantly scrolling social media for a lack of better use of time, but after the exams ended half a month ago I decided to cut it off and enjoy isolation for the time that I'm at home. So I logged out of facebook and instagram, and use the rest of my social media as usual, meaning I open them rarely. What this has translated to practically is that I have been using a couple of other apps a lot more than I used to in the past. For example, tiktok. I used to hate the app with passion for no reason in the past, probably because of herd mentality. I even deleted an account I had and left the app. But in the start of this year, I joined again and so far I have been using that app progressively more to a point where it's starting to make me worry. So I decided, if this facebook/insta withdrawal works well, I may as well for the next year, decide to isolate myself from all forms of social media whatsoever. Maybe that will provide me with some of the self control, whose lack has been dawning on me and subsequently eating up my self esteem in the recent days. What strategy do you suggest I take and for how long do I sustain my complete detoxification?

Next is related to a thread I posted earlier about how I have become dependent on cigs to mend my loneliness. Here at home, such bursts of loneliness don't hit me as much and thus I have not yet, in my over 2 weeks have lighted one. This means that the time in which I would have finished more than a pack, I have gone without it, which I'd say wouldn't be anything significant if you'd told me that 6 months ago. But this semester, I was starting to worry. I'm gonna get my lungs back soon so I'm happy I have kept my composure so far. It's not like it's hard for me to get a puff here either, I could just walk 20 mins and I'd be pretty safe but it's just something I haven't let my mind think about, except for now that I'm, in a way, updating you guys on my current situation.

Have you been in a similar situation? Trying to let go of harmful habits with nothing in mind that could act as a replacement? It gets restless at times thinking about what I will do now that these things that used to keep me occupied, are no longer there.

(Also, to be completely honest, I have taken a few puffs here and there even after returning, but that's a rare meetup occasion since Dashain and all. Plus I have been sober from drinking for about 3 months now.)

What activities do you suggest I take up to try to relieve the mental burden and alleviate this void I feel when there's nothing to do? I haven't been able to hold myself accountable for those exercise and meditation sessions. How do you maintain such level of discipline in your day to day life?