I refund most of the alpha games I buy on steam. Valve knows a lot of alpha releases are just milking cows for people/companies that love to exploit teenagers and their parents wallets, so most of the refunds are approved. They changed the 2 hour grace period of refunds to something similar to "no excessive game time or usage", so unless you played like 10 hours straight or kept the copy for a few days, it generally is approved.
I hate today's culture of alpha titles, it's disgusting how people let companies exploit them. Buying an alpha title and not refunding is basically telling them "hey, please let me buy your unfinished product without you having to guarantee anything". Look at PUBG, Raft, No Mans Sky, HZ, and all other alpha games. It's impressive how Valve, even though they make a lot of money out of it, allows their Steam platform take a big hit in both quality control and reputation.
I've got no hard feelings towards DayZ, it was the first alpha game I ever bought back on the very release day on Steam. This game has still given me value and I wouldn't refund it for anything. I however regret spending money on all other alpha titles. They are disgusting, and they only offered early alpha access because DayZ did, they saw how exploitable the market was. BI and DayZ though, they have earned their share of the money. None of the others did.
Everyone should refund alpha games. Play it a few hours and then refund, let the producers know that it's unacceptable to milk the market only to never live up to any expectations. A big practical example of this is PUBG, it's a complete mess and they never fixed anything important, because they couldn't - netcode being one of the biggest issues to date and it never got any love.
OP: I don't think you'll get a refund, factors like time owned and played are considered and you most likely owned it way past the refund window.