Please tell me where I'm going wrong with hot air!

[G-Gamer]

So I'm trying to get into micro soldering, repairing tech etc.
I bought a load of equipment, The YIHUA 853D 2-in-1 station, 1080p Microscope with 10", I do not have low-melt or leaded solder yet, I have tried flux 'paste' in a tube, very liquidy seems to blow away, I've tried flux paste in a tub, still no luck.
I have tried 3 different boards, a router, an Xbox One Fat and now a Pi400, none show ANY signs of melting solder, components don't budge.

My method:
Preheat board with hot air (Small nozzle as it's directed, as I'm told) at 250c
Apply flux to component
Hit with hot air at 350,370,400 - nothing budges.
I know about heat transfer to larger components and the board being a big heatsink but I'm supposedly doing everything right bar the low-melt, but that shouldn't make a difference that much if I'm using the above temps?
I have ordered some low melt solder to try lower the temp, but I need to figure this out, everyone makes it look so simple so I'm unsure where I'm going wrong, I have tried HDMI, USB, random small chips and caps, nothing ever moves...! I have tried using my iron and wick to remove the legs but that didn't help either

[m1ch43lzm]

Don't use very small nozzle 3mm, try with 6-8mm nozzle, keep practicing on scrap boards, you don't want to cook the parts by heating them for long time, it also depends what components you want to remove
Also the distance from the nozzle to the board matters, not only the temperature/air flow, try 430-450C; it also depends on how powerful is the heater in your hot air station

[G-Gamer]

I have the fan speed on 1/8 and it seems to just blow all the solder away
just takes the life out of me I’ve been trying to just remove a component for 3 days straight, I figured unleaded solder melts at 370 with my iron so thought that would be a good target for hot air

[m1ch43lzm]

HDMI and full size USB connectors of course require more temp and a bigger nozzle, try with small resistors, capacitors, ICs first
Temperature at the PCB surface is lower than the temp you set in the hot air station, try 450 as a starting point, it also varies with distance, try getting closer, less than 1cm
On a smaller/thinner PCB like a phone or tablet it will take less temp for the solder to melt
And also get a roll of leaded 63/37 0.4mm solder