guide me on how to avoid this issue permanently
That's not possible. Itch is fighting malware and is on the losing side.
Giving you a blue print to avoid delisting/quarantine - if there were a recipe for that - would mean to give all the criminals the same blue print.
There is malware uploaded and indexed every day. And reported malware is not removed for weeks and months. Either they are swamped, do not believe the reports or whatever. Quarantine, deindexing and long waiting times are a side effect of that fight, in my opinion.