The Telcos are not making many promises when it comes to 5G at the moment. The technology is brand new and very temperamental. You could get 40Mbps while your neighbour might get 400Mbps. On average Optus customers are getting around 164Mbps but that's just an average.
FWIW the Optus 5G guarantee isn't actually a promise that you will get 50 Mbps minimum but its a promise that if you don't get better than that then you can return any equipment and leave anytime.
No doubt Optus is working to improve the 5G experience and as more towers in your area come online you should see improvements. In the meantime have you played with moving the equipment outside and testing etc. 5G is very dependent on line of sight so grab an extension cord and try moving the equipment around. Its not necessarily a solution but you could test if you can get better speeds say out by the mail box.
Otherwise its either take what you've got or leave any time - pretty reasonable deal IMO.
I live in Newtown, and like most around here I live in a terrace. I have a front window and a back window. Thankfully the nearest tower is across from my front window because putting in my bathroom might be a bit weird.
And yes, I followed all the instructions, as did my friend. It just seems odd they are boasting 164 as an average. This means to balance what we are getting someone else must be getting 250mps, which seems unlikely.
Optus keeps phoning me each week asking if I am over 50mps yet.
No tech visited. They just said to go to their app to find the nearest tower and use that to decide where to put it. As I said, thankfully my front window faces almost directly the right direction. My modem thing couldn’t be better placed unless it was on the roof.
And my friends is much the same. She did move it closer to the window after a few days, I presumed she did that as she was instructed to, but as I said, my coverage is better than hers though she is 3 times closer to her tower than I am to mine.
Coincidentally, and unfortunately, it is now completely dead. Peak time I suppose. I just asked my friend who is using it how what she is getting and she said she is down to 5mps.
As for moving things around, I live in a little terrace. I gave one front window which gratefully faces almost directly toward the nearest tower. I couldn’t get closer, and judging that it had now conpleteky
Interesting its happening to both you and your friend. It could be a temporary network issue (I'd report it to Optus directly). Hopefully it will come back on line but if not then I guess you're lucky the NBN is an option. There are plenty of month to month plans that you could grab and perhaps try 5G again later in the year. Let us know if you'd like any NBN advice.