It's a bit like a henn-egg problem: Debian does no longer support i386 as many projects have dropped their support. Projects drop their support, because there are only few systems with that architecture still in use...

From trixie, i386 is no longer supported as a regular architecture: there is no official kernel and no Debian installer for i386 systems. Fewer packages are available for i386 because many projects no longer support it. The architecture’s sole remaining purpose is to support running legacy code, for example, by way of multiarch or a chroot on a 64-bit (amd64) system.

https://www.debian.org/releases/trixie/release-notes/issues.en.html#reduced-support-for-i386