Sorry mate, there aren't any springer DMRs AFAIK. Only bolt actions or cheapo shit "bb guns"
Even electric DMRs aren't very good unfortunately. There was a thread recently you should still be able to find in the last few pages, basically they look like one but internally they're going to be just the same as any normal electric rifle and they need a lot of work to perform as you'd expect from such a gun.
You'll see we recommend the G&G Combat Machine a lot to beginners (as DMRs / snipers need a lot of expensive upgrades and experience, gas guns need maintaining, sniping is away from the action and as a new player I would want to play the rifleman role)
If you want a spring gun your best choice is a tri-shot shotgun. There isn't actually a huge choice when it comes to them. All are basically manufactured by the same company but can be sold / distributed under different names. So for example DE (Double Eagle) or UTG sell them.
Will set you back probably £50-£60 (there's a full stock model, collapsible stock version and no stock / pistol grip one)
I know it isn't the answer you were really wanting but hope this helps.
Welcome to the forum by the way!