Pete, I agree on print speed being about 50mm/s but nothing to stop you backing that off to say 30mm/s. I am very wary of printing at 0.2mm layers with a 0.4mm nozzle. The squish/weld factor is not great and I associate it in my prints with most failures. For setting up and calibration I would ONLY recommend 0.1mm layers. If you are under extruding as it appears this allows a fighting chance for the filament you do extrude, to get pushed onto the layer below. It also means the first layer is pressed well onto the bed, you should be able to print onto a cold (20℃>) bed. One of the bed materials I use here is Perspex, and cold the bond can be too good. I will juggle temperatures and start the first layer at 190℃ and switch to 205℃ a couple of layers up, with PLA once the foundation has taken, back the bed temperature off to ambient, or down to 30℃
Check in your printer settings to see if there is an initial offset for the first layer, this can catch people out. They think they are printing 0.1-0.2mm and the offset adds another 0.1mm or more, so the filament never gets pressed onto the bed.
Please give the extruder a test, make sure it pulls 100mm of filament when instructed. Is your machine direct drive or bowden feed ? You must get that 100mm extrude as accurate as you can, that determines the metering of molten plastic. Run the test again this time feeding plastic through the hot end. Mark your filament with a Sharpie, say 110mm away from the extruder, now extrude at a slow rate 10-20mm/s and measure your mark to see if 10mm is still sticking out the extruder. If not change the step rate per mm in your software or find out if the filament is slipping/grinding in the extruder.
Measure the filament that gets extruded once cool, is it <0.40mm ? If yes, you could have a nozzle blockage or damaged tip (a hot end crash can put a burr on a brass nozzle that can curl the filament) Use a gas jet pricker to clear a hot nozzle, but be careful as this can also open out a brass nozzle. Another trick is to remove the nozzle and heat it to 300℃ or so with a heat gun, this will pretty much vaporize any remaining PLA residue (watch it bubble out and smoke)