Is it possible to use R2 on non Cloudflare dns website?

I'm in a project that I cannot migrate to Cloudflare's nameservers because of regulatory reasons.
I want to use R2 but not move the domain to Cloudflare and replace the old s3.websitename.com instead of the r2.dev subdomain.
Is this possible?
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Is it possible to use R2 on non Cloudflare dns website? - Cloudflare Developers