I just don’t want to accept him not being in contact then boom when he feels like it, picks me up again.
Yes.
You had good reasons for finishing this relationship ... & it's entirely possible that he will be no better for you as a friend than he was as a boyfriend.
I don't think it's healthy for you to even be entertaining worrries about his ability to pick you up / drop you at whim. It sounds like a mismatched power balance, & you might feel a lot better if you simply choose not to expose yourself to it.
No need to analyse it & certainly not to discuss it with him.
Just block on all socials, & keep it professional from now on.
Better for your mental health, & much better for your work life.
Think I should give him a wide berth actually after this.
You certainly should - he's a flake. While I agree with PP above that he doesn't owe you anything, all the dramatics about his phone/the internet/his kids phones is shady & unnecessary.
Cut his dramatics out of your life, & you won't need to waste any time wondering about him, his motives, or his flakey behaviours.
No need for any drama from your end - just quietly block him on all socials, & stay breezily professional at work.
If, following his on/off shenanigans, he notices he is blocked & has the temerity to question why, tell him you have decided that it's better if you keep all interactions on a work footing from now on. No need to explain or justify - it's not a debate.
You simply didn't enjoy his nonsense about social media comms, & prefer not to engage any further.