Interest rates are just how a private property market economy navigates certain naturally occurring tradeoffs, wherein you make a sacrifice of options that are slightly below your personally-market-clearing rate of return in order to free up resources for options that are slightly above your personally-market-clearing rate of return.
If you have to overcome interest-based finance, you might need a system of practice with a way of organizing and incentivizing a community's productive labor and capital allocation over time, that demonstrates itself to be better at benefiting from that kind of natural wealth-producing option, in a virtuous and balanced way, than the financial system is.
To give some idea of what this could look like: In an imaginary universe, where you had people who really understood on a visceral level how tradeoffs over time worked, and where they all had a consistent idea of how much they all cared about themselves and their beneficiaries now and in the future, you could get a situation where those people were naturally as productive as if they'd been lending and borrowing at interest, without any lending or borrowing at interest. What would normally have been a default on a loan in our universe would then, in that imaginary universe, just be an understandable failure from someone who was genuinely trying the-right-amount-of-hard. Not just in how hard they were working, but also in how carefully they were thinking through possibilities and realistically planning around long shots and misfortunes, and, in the long run, in how attentively they adjusted their habits of paying attention to some aspects of the world and not others, given the effects on what wealth-affecting possible outcomes they noticed. But then, all of that is like saying "in an imaginary universe where Communism worked". In our universe, if you tried to arrange people that way without either market discipline or a lot of non-obvious cultural technology, the enterprise would fail on many levels of kybernesis simultaneously. The usual economic terms are "free-rider problem" and "principal-agent problem", and there's also the sociobiology/ev-psych "coefficients of relatedness" to consider.
There's a little bit of social science about why a few communes succeed and most fail. Supposedly there was a finding where religious kibbutzim with more hours collectively spent in communal religious ritual time per week were more likely to succeed than secular kibbutzim. But I didn't find a citation. I did find that papers liked to bring up the question of what it does to a kibbutz or other kind of commune to be in implicit competition with an external market economy. That literature might be a good place to start reading, to understand what you'd have to get right.
Re: Q
If you have to overcome interest-based finance, you might need a system of practice with a way of organizing and incentivizing a community's productive labor and capital allocation over time, that demonstrates itself to be better at benefiting from that kind of natural wealth-producing option, in a virtuous and balanced way, than the financial system is.
To give some idea of what this could look like: In an imaginary universe, where you had people who really understood on a visceral level how tradeoffs over time worked, and where they all had a consistent idea of how much they all cared about themselves and their beneficiaries now and in the future, you could get a situation where those people were naturally as productive as if they'd been lending and borrowing at interest, without any lending or borrowing at interest. What would normally have been a default on a loan in our universe would then, in that imaginary universe, just be an understandable failure from someone who was genuinely trying the-right-amount-of-hard. Not just in how hard they were working, but also in how carefully they were thinking through possibilities and realistically planning around long shots and misfortunes, and, in the long run, in how attentively they adjusted their habits of paying attention to some aspects of the world and not others, given the effects on what wealth-affecting possible outcomes they noticed. But then, all of that is like saying "in an imaginary universe where Communism worked". In our universe, if you tried to arrange people that way without either market discipline or a lot of non-obvious cultural technology, the enterprise would fail on many levels of kybernesis simultaneously. The usual economic terms are "free-rider problem" and "principal-agent problem", and there's also the sociobiology/ev-psych "coefficients of relatedness" to consider.
There's a little bit of social science about why a few communes succeed and most fail. Supposedly there was a finding where religious kibbutzim with more hours collectively spent in communal religious ritual time per week were more likely to succeed than secular kibbutzim. But I didn't find a citation. I did find that papers liked to bring up the question of what it does to a kibbutz or other kind of commune to be in implicit competition with an external market economy. That literature might be a good place to start reading, to understand what you'd have to get right.