A bad workman always blames his tools. Swap mice next time you're down and I'll still kick your arse at a game of your choosing!*
Tbh though I don't find high dps mice all they're cracked up to be. I only ever switch the mouse between 800-1000 dpi
iirc depending if I'm in Windows or Debian, simply due to their differing default mouse settings, I don't recall ever switching DPI for gaming! I bought my G9 for the adjustable weights+grips and decent build quality more than anything else. I'd be perfectly happy with one of those Dell mice, apart from the fact that that the feet on them are crap, they scrape rather than slide over surfaces!
I do however swear by a decent mouse surface, going from just the desk to a gaming mousemat massively improved tracking. Cheap mousemats are no better than a desk, that goes for both plastic and fabric
imho. I've got no idea about hard topped gaming mousemats but a decent cloth mousemat is my weapon of choice. The downside to cloth mousemats is that they do accumulate dirt/grease, even if they don't look dirty - I stick mine in with the washing occasionally and mouse movement becomes noticeably less sticky!
In your case I'd stick with the Dell and just buy some replacement PTFE mouse feet and a decent mousemat. The SteelSeries Surface QcK mats are reasonably priced on Amazon, at least in comparison to some gaming mats!
*TF2 excluded