DDoS? It’s cheaper to hire botnets to attack than to defend. You’d most likely still be knocked off even just by the amount of traffic that leaks through your proxy before the VM gets cut off at the data centre. Specifically: it is much more likely that data centres will give higher thresholds before null routing your VM than your residential ISP would be wiling to tolerate.
Brute force on shell? SQL injection? Remote shell execution? Deploying the extra layer will not protect you from these as your own proxy will not give you WAF.
It is always important to know why you’re doing something, before anyone can prescribe a solution.