Indonesian banks generally do not offer mortgages to foreigners. However, it is possible to take out a second mortgage on real estate in your home country. The released funds can then be used as you wish, for example, for purchasing real estate in Bali.
Indonesian banks can provide loans if you already own property in Indonesia and can demonstrate that this is part of healthy businesses. Keep in mind that interest rates are significantly higher than what we are used to in the West.
Foreigners can finance indirectly through a second mortgage or loans on existing Indonesian real estate, but keep in mind the high interest rates.