So here's the thing.
Printing stuff at speed with a fairly large bead - in this case 150mm/s at 0.3mm leyer height and a 0.5mm nozzle - is almost entirely down to how good your filament is and possibly what colour it is.
Must have wasted a couple of hours trying to get yusu black filament to do this.
Not a hope in hell. It's thick ad blobby and clearly only for use i fairly slow prints.

The mystery roll of red pla I bought a while back and was supposed to be sunlu - but clearly isn't, is now cranking it out with no problems.
Also ordered more flashforge as it's gone down to £12 and next day free delivery with my amazon prime.
The red flashforge is easily the best pla I've used since the original wood coloured reprapper-tech stuff stopped being made.
So threw in a roll of flashforge white and black as well.

Now the more I use different filaments, the more I believe it's actually a lot more to do with colourant, than it is with manufacturer,
For example Green filaflex and ninjaflex, prints easily on my replicator clones. But red tpu just won't print at all.
Alexa will print any of them. Which is counter indicative as she's a bowden.

Thinking there is something in the red colourant that lets filament flow better and keeps it that little bit more flexible.
But as no manufactuer currently lists pla ingredients - it's just a theory based on the last 3 1/2 filament usage.

And anyone who still believes pla is brittle needs to take a 30x30mm aluminium strut, wedge it into a pla corner and bang it up and down - hard - on a concrete floor.
I also threw one of the old corners up i the air and let it crash down on the floor - still concrete - it bounced, of course it did :-)

Got a little warp on the flashforge corner - forgot It was set up for printing really small things (strutnuts) and it needs a bit more smoosh for larger items.
Might work - we'll see.