I bought a 12-month Xbox live gold pass and Microsoft convert that to a 4-month ultimate...

It didn't come with 4 months of Ultimate, it converted the Gold you added to 4 months of Ultimate. If you already have Ultimate on your account and you add a standard Gold or Game Pass code, it converts the time to Ultimate (since Ultimate already includes them) at a conversion rate based on the price rather than time. So the 12 months of Gold was converted to 4 months of Ultimate since a 12 month Gold is equal in price to Game Pass Ultimate.

Yes the auto renewal is off already. I have the Game pass ultimate until May 25. I already bought a new 12 month xbox live gold card but when I try to redeem the code it says my 12 month
gold will be automatically convert to a 4 months xbox game pass ultimate which I don't want. I want the 12 month of xbox live without the game pass. Do I really have to wait until my xbox game pass expired before I can redeem a new xbox live gold (without
the game pass ultimate)?

When you bought your Live Gold subscription, did you have an Ultimate Game Pass subscription active when you purchased it by any chance? That would explain it as if a UGP sub is in place, any Live Gold added is automatically converted to UGP...12 months gold would have been converted to 4 months Ultimate Game Pass.

so you're saying if I purchase a Xbox Live gold membership prepaid card for 12 months while Xbox Live Gold Pass ultimate is enabled it'll convert those 12 months into Xbox Live Gold pass ultimate

It means that the time you got left on those suscriptions will be automatically converted to Ultimate Areeb.

Here is the convertion ratio:

1 month of Gold = 20 days of Ultimate

3 months of Gold 50 = days of Ultimate (1+ month)

6 months of Gold 79 = days of Ultimate (2+ months)

12 months of Gold 4= months of Ultimate

24 months of Gold 8= months of Ultimate

1 month of Xbox Game Pass (Console Games)= 20 days of Ultimate

3 months of Xbox Game Pass (Console Games)= 2 months of Ultimate

6 months of Xbox Game Pass (Console Games)= 4 months of Ultimate

12 months of Xbox Game Pass (Console Games)= 5 months of Ultimate

24 months of Xbox Game Pass (Console Games)= 10 months of Ultimate