Still waiting on an offer letter

I interviewed for this multinational company (> 10 000) at the end of January, and received a call from HR and hiring manager to tell me that I was the selected candidate the first week of February. Sent an email with the information they needed from me afterwards, etc.

I've followed up about a week and a half ago by sending a text to the hiring manager (he initially contacted me like this) and was told they were waiting on approval from higher ups (from the CFO department). Two days later, HR called me to reassure about the same thing and that they are trying to get the final signal-offs but it takes some time, and it would be a pity to lose out on a potential hire over this.

Now, I don't know if they are marinating me/something is happening in the backstage, or if this is just bureaucracy. I am a bit worried over this because I am unemployed and don't really know what to think or expect. I keep applying to other jobs meanwhile but damn, this opportunity looks very good salary and skills development wise and it would be a pity to miss out on it. What do you guys think ?

NB : English is my second language, sorry for grammar