custom explorer map not working in 1.18

I am using a code like this one in 1.17 to get a custom explorer map to locate a shipwreck.
As soon as I updated it to 1.18.2 it's no more working and I just get an empty map.
Maybe there are any issues in the code but I dont think so because in the 1.17 there were no problems...
There is also a similar report for 1.18.2 pre release 2 but according to them it has been fixed in the 1.18.2 pre release 3