Well that's the thing - I'm not willing to build them. I wouldn't know where to start, even. And no ambition to learn, whilst Firefox and uBlock keep going. Seriously why should I? Maybe someone more able than I can share their knowledge with a pointer to a guide that says why this is better than what I have, and how to get it running on my Windows box.
My current position is to step wide and rather carefully around anything by/from Google.
So you say your current position is to be rather carefully around anything by/from Google, but you trust Internet randos to build the binary of the browser you use?
Okay.
Do you trust Internet randos to build the binaries of the compilers you use to compile the Chromium source code? How deep do we need to go?
A more practical depth would be to bootstrap with GNU Mes, which is a source based bootstrapping path, that begins with a tiny scheme interpreter (~5000 LOC of simple C) and a C compiler written in scheme that are mutually self-hosting.
These tools can compile a slightly patched version of TinyCC that is self-hosting. Using this C compiler you can bootstrap a bunch of gnutools (glibc, binutils, gcc) and using these tools you can bootstrap a full Guix Linux distro.