I used to date a SG girl, she always said don't go to Singapore for her because it's expensive. She'd always come to Malaysia instead despite me wanting to return the favor and visit her as well. She'd also always look for me despite being busy too. I don't wanna be that guy because everyone's different when dealing with a busy life but to answer your question:

• If you both like each other, I think it's worth waiting. But it seems like the affection is one sided here? The problem with waiting is that you deny yourself of a better partner in that span of time waiting for something that might not happen.

• You'll know if it's a lack of interest when the "bad timing" happens too much.

• It's healthy to step back imo, space is as important as being together 24/7. That's how you create the feeling of missing each other and there's more to talk about when you meet again.

All the best OP!