Hi
Right now if you were to ask apple for a refurbished iPhone SE (1st gen) they would ask you to upgrade as I don’t think they sell or refurbish this model any more
If you asked them for a replacement unfortunately they would most likely tell you to upgrade to the newest model
As for getting a replacement that’s refurbished you can find loads on eBay and Amazon but pay close attention to who you are buying it from
Your phone isn’t vintage yet but when it becomes vintage you can still get parts online for various retailers
As for you currant phone if you tell us what wrong we could help you fix it but that’s entirely up to you
Hopefully this helps
Any questions please ask
Thanks:-)