Or go for something like this:
I will just get the " Sapphire Radeon RX 570 Pulse 4096MB GDDR5 PCI-Express Graphics Card".
thing is your almost at a new PC!!!
Will buying that improve my computer performance or allow me to run things faster or should I just wait and buy all this stuff together? Like, what would you do if you wanted to play Dota 2 primarily and occasionally other things?No, don't get that GPU. Your PSU doesn't appear to have the power cables for it. Without replacing the PSU you're limited to the GTX 1050 Ti.
I do concur with the other comments about the SSD.
I would just get a new Ryzen 5 2400G CPU,
Ah, you linked that video now I'm just watching lol
Is it worth changing the ram card into one 16gb?I would say though, you only have one DDR4 DIMM. I would get another 8GB DDR4 dimm of the same type so you get the Dual Channel advantages.