Area-51 R7, CPU, GPU upgrade options?

I'm quite new to Alienware and realised that the Area-51 R7 is already pretty much dead. I was thinking of either making a new pc with individual parts or upgrade my Alienware. However, I don't know what GPU's and CPU's are compatible? I'm thinking of getting a 2080 Ti so could anyone recommend a CPU that wouldn't bottleneck the GPU and would be compatible in my motherboard? My existing GPU and CPU are an Rx 580 and a ryzen threadripper 1900x