Is that DDR4-3600 C14? Pcpartpicker has 2x8 GB sets listed at lows of $170-$198, so curious where you're getting a set for $300.

Provided you're on 1080p and already packing a 5.2+ GHz Intel or any Ryzen 5000 series CPU coupled with an RTX 2080 Ti/3080 (I know scarcity is a prob), play games competitively and can accept that hardware isn't your limitation, then sure YOLO. It's not like it's years of car payments or anything.

As for DDR5, it's apparently already being made, just waiting on Intel/AMD to integrate into their respective hardware. Unlike the transition from DDR3 to DDR4, it looks like it'll be faster right out of the gate so I'm afraid your computer will spontaneously explode and force you to upgrade.