The command line program, wget, can do most of what you want, but being a command line tool there's a slight learning curve.
Googling for alternatives with a GUI I found visualwget but I can't personally vouch for it (or its safety of the executable on Github) as I've never used it personally.
Ungoogled Chromium from Portapps: This adds the portable feature, which is the only missing item in Ungoogled Chromium. The best solution for you if you just want Chromium without Google.
Iridium Browser: An another Chromium browser. In fact, this is quite similar to Ungoogled Chromium and it meets all the requirements. As an extra, it's also privacy-focused ...