The MB will support those CPUs with a BIOS flash-don't for get to flash FIRST!
Should give some gaming improvements, and, of course, it'll run those games that demand a 4 core CPU currently denied to you by the dual core pentium.
Don't expect miracles, the GTX750 is a very low end card by current standards:
https://www.tomshardware.com/reviews/gpu-hierarchy,4388.html but you should get playable gaming at HD rez if you keep the settings low/med.
Good news is that a upgraded GPU will really fly! And with the cryptocurrency boom largely over prices are returning to normality, even used parts have dropped in price significantly over the last couple of months so ( maybe, budget permitting ) you could drop an upgraded GPU in later and...