My first thought. Do you really need to change because you broke your macbook, or do you want to change because its "trendy" ?

Few problems:

CPU is slowing down lately, even switching tabs in Chrome sometimes takes a 1sec to actually render the page.

Disk is getting too small. I use a lot of VMs for work and I never have enough space to run them all.

Laptop is dead, if I replace it I will be without a laptop for weeks according to Apple.

I let it drop once making the fan very noisy, not really a problem just annoying.

So, you've dropped the laptop and the fan became noisy, which would also lead to CPU throttling because if the fan isn't working right, CPU is going to overheat and your laptop is going to suffer as the result of this.

Did you even take the back off to try to reseat it or clean up the laptop? You can try to take it to an authorized Apple repair shop to see if they can re-seat the fan/clean up the fans for you.

I have same '12 rMBP and the performance is just as snappy as it was back in '12 and I've never reinstall OS either, so it's all consistent and snappy.

I have no plans to upgrade this because there's nothing else that comes close to replacing it right now, not even '16 rMBP.

As for the disk, I put my VMs on external SSDs, works great. Certainly cheaper than replacing the laptop and easier to upgrade every year to more storage.