If you're not keen on drawing down your Bitcoin position you'll have to wait for more mature products, where you can borrow against it without knee-capping yourself on the interest rates and have the margin should your loan to value fall short.

I don't see this happening for some time on real bitcoin

I think it rolls out first on ETF products, since it's pretty normal to borrow against your ETF or sell calls and generate an income on your position

I don't know how many custody providers would jump into this market for real bitcoin, but anything is possible