May I offer some thoughts from "A Local Resident"?
Start by entering 51.666700, -3.924269 into the search box of Google Maps, you should be looking north from 'Morriston Crossroads' with Prentrepoeth Road to the North West(left) and Sway Road to the North East (right).
Next open:
https://maps.nls.uk/view/135196678 [nls = National Library of Scotland], {O. S. 25 inch series published 1917, this is the earliest 25" series map of the area, that I know of available on the internet} using the little red slider box move to a point just a little above halfway up the right-hand edge of the map.
And finally open:
https://www.bbc.co.uk/news/uk-wales-south-west-wales-41203669 and scroll down to the third image.
I am inclined to think that the "P.H.", seen in the 'nls' map on the north aspect of the junction is, or could be, No.4 Pentrepoeth Road (by earlier suggestion in the thread: formerly Swansea Road?). No 8 is seen today on the streetview image by tweaking the view!
The image on the BBC website is indeed the same junction albeit some years prior to the current buildings (c.1932) seen in the streetview image.
I trust this adds a little local input to the background of the thread.
Enjoy the images and stay safe.
JohnG_Swansea.