Looks like that Motherboard only supports up to i7-7700. A more modern CPU like the i7-9400 series would be a step up, but you will need a new motherboard for that. Since you will need a new motherboard, you might as well get the most CPU you can afford. You can also do better on the memory speed if you are going for a new motherboard. You can likely put off the memory upgrade to put your money towards the CPU and Motherboard, but be sure to check compatibility of the old memory with the new board.