Is there any way to reactivate a lost/stolen iphone?

Hi so I have had an iPhone 6s for around a year and a half now but that wasn't always the case. Before I got my 2nd 6s, I had an original one that i bought at the verizon store, but a few months later I lost it and had to get an insurance refurbished replacement iPhone 6s from Asurion. This phone is fine and was fine for a while and worked as good as I thought it would. Around 6 months after I got my replacement phone, I ended up finding that original iPhone 6s I bought at verizon inside of my couch. Without any thought, I figured it would work off the bat with my sim card, so i put in my sim card on my current iphone to find out it couldnt be activated. After putting it back into my replacement iPhone I was using, I ended up having to go to verizon because the sim card was deactivated due to it being put as a lost or stolen iPhone in the verizon network, but the phone itself works fine with Wi-Fi. About a year after all of this happening, I use both phones but my insurance Asurion iPhone 6s is noticabely slower and has worse battery life then the original iPhone 6s I bought and ended up finding. My question is, is there any way I can reactivate my lost and unable to be activated iPhone easily, or would I have to go through a lot of trouble and it would just be easier to wait until my upgrade. Thanks, and sorry if this was confusing to read as it is a lot haha.

No. Once the IMEI has been blocked it is an irreversible step.

That iPhone also no longer belongs to you: it is the property of whichever insurer paid out for its replacement. If you contact them to offer the phone back then they might allow you to buy it back if you just wish to use it as an iPod.