iPhone 12 Pro: battery replacement, MagSafe power bank or upgrade to 13 Pro?

Even though my iPhone 12 Pro is getting close to the end of its life, I’m still very satisfied with its performance and design, and I don’t really have a reason to upgrade.
The only real downside is the battery life.
Would it be better to replace the battery at an Apple Store for around €100? (It’s currently at 87% battery health.) Or should I buy a good-quality MagSafe power bank instead?
I was specifically looking at the Anker MagGo Power Bank MagSafe 10,000mAh Qi2, which costs around €60.
Alternatively, I could upgrade to a 13 Pro. How much would the difference in price be, and would it actually be worth it?
What would you recommend?