The machine is fully supported by Mint, but because it's a non-free firmware driver, you will need to add either an ethernet cable, or a usb-to-ethernet adapter, or you could tether from your phone. Then you can install either the b43, or the wl driver (depends which chipset you have), and then wifi and bluetooth are going to work like a charm. I had to do the same on my mac mini. Apple uses broadcom chips that don't have full open source bits, so they're not part of the live ISO. You'll first need to find another way to get to the internet, and then fetch the right files.

I had a similar issue with Mint on my Latitude 7480, ended up using Fedora where everything just seems to work.

Best advice I can suggest is always use a live USB because if something doesn't work there it won't after install either.

Connect to ethernet and update drivers maybe

rmmod b43
rmmod bcma
rmmod wl
modprobe wl

Broadcom drivers.

Use hotspot or tethering from phone to give the Macbook Internet, and update the WiFi drivers and firmware. Or get an ethernet adapter for USB port.

Had a similar experience with a '13 air. Everything works, except wifi. F'n Broadcom. Don't remember how I got a working driver, but the next time it breaks I'll just try to order some compatible wireless card instead.

Check your region settings. Maybe you are not listening on the right channels for your country.

After installation, run driver manager. It will install any proprietary drivers, and firmware. You will need to provide the laptop an internet connection through an ethernet cable when you run it though.

https://linuxmint-installation-guide.readthedocs.io/en/latest/drivers.html

Yes, Macbook Pro 2017 has issues with Linux. See here for what does and doesn't work: https://github.com/Dunedan/mbp-2016-linux

Some workaround fixes here: https://gist.github.com/roadrunner2/1289542a748d9a104e7baec6a92f9cd7

I had constant issues with wifi when running mint ~3 years ago. I never managed to fix it and instead switched to fedora.

Have you by any chance configured the wifi channels on your router/AP by hand? I had a problem a long time ago, where some device would assume it's in the US, while the AP was set to another country code and you could choose wifi channels that in the US are verboten.

I think the Driver Manager may be able to help you select the correct one or at least make the correct one permanent.

I'd try another distro - I've had issues with Mint and wifi in the past. MXLinux saw wifi when Mint didn't. Or maybe Ubuntu.