I wish it was common practice to unbloat containers, but it seems needlessly hard to do and undervalued.

Most containers are built with layers and removing from one layer doesn't make things smaller.

older versions of docker don't help with squashing (except with experimental turned on)

I think you might be able to do with multi-stage builds and COPY

but... it's not valued

I very much enjoy dive[1] for this purpose, though it doesn't seem to be maintained anymore...

[1] https://github.com/wagoodman/dive