Trying out OpenWrt for the first time using Virtualbox. Can't share internet to Host computer

Hi everyone,
I've now spent a good two days trying to follow tutorials and browse forums. figured its about time to ask my question here.

Decided I wanted to give OpenWRT a go, I'm using a 4G wifi hotspot (NetGear AC800S, plugged in USB3, it does feature a USB passthrough function).
for the router itself, I do have a Raspberry Pi3b, but for now I was just testing it on VirtualBox (latest version from website).

Now what really doesn't help, is I'm very new top OpenWRT and Virtual machines in general. I've followed the "OpenWrt on Virtual Box" guide ( a few times now. Getting the VM to use my 4G modem's internet through USB took over a day to do.. but I found out the correct packages I needed after trying some of the USB tether tutorials
(kmod-usb-net, kmod-usb-net-rndis, and kmod-usb-net-cdc-ether). And then creating a new interface using the new device.
I'm able to update packages and ping successfully, (with my host computer being disconnected from the internet).

from this point.. I just have absolutely no idea how to share this USB3 internet in the VM to my host computer... I've read people suggest setting a static IP, but changing IP on my host only adapter will make me lose access to LuCI and SSH.... while setting a static IP on the USB modem connection simply makes me lose access to the internet.

Thanks for reading and completely open for suggestions.

Running a router firmware in a VM is quite a bit more complicated than on real hardware, as you need to be quite familiar with the hypervisor intricacies to get the networking side of it working correctly - and USB pass-through isn't really trivial either (even more so, that can be quite buggy for timing sensitive services like WLAN cards or cellular modems). Do yourself a favour and just give it a try on real hardware, all you need is a sdhc card for your RPi or an old USB stick for any x86 device.

Sounds like good advice. Thanks. I think I'll give up on it for now..
when I get some more time I'll try the Pi.. only thing with that is I still use it for Lakka and and Kodi on the odd occasion.. and I would hate to need to have a keyboard and screen handy everytime I want to change it's function. anyway, that's an issue for a different forum..
thanks again for your input.