I strongly disagree, not for the fun of it but because I have gone through the same thought process as you.
My iPhone 6 GPS was working great until the very moment I upgraded to iOS11. I spent weeks thinking it must be software until just before I gave up and throw the phone to the bin I decided to give a go to replacing the GPS and WiFi antennas.
Well guess what I lost weeks talking to Apple because my GPS is back for good. No software update fixed it, me replacing the parts fixed it.
Believe me or not, I now know what solution was the only real one to go for since the beginning.
It has not stopped working once since the parts have been replaced.
And to make things better I had the battery replaced for 29$ at the store.
So now my iPhone 6 has a great battery life and a functioning GPS.
The faster you will replace the parts the faster you will put yourself out of your misery.
Now beware, this worked for an iPhone 6, it might not work with other models. Also, I replaced the parts myself, it took me 3 hours, I bought the best parts and tools and was extremely careful. I also followed religiously the iFixit guide and read all the comments. It's not for the faint of heart though, you do need to have a good eyesight and have a steady hand.
I can't advise highly enough to get these parts changed. But I know that I had to be desperate to end up going through that hassle of doing it myself. Therefore I understand all those who still want to believe that it's only a software problem linked to iOS11 and that it will can be fixed with another update.
Indeed it happened simultaneously, as it happened simultaneously to people updating to iOS9 and iOS11 (Google search will show you). It's strange but it's possible for software to fry hardware.
All the best