Well… Apple loves making things hard! Sadly, it’s not a simple. The TouchBar is glued down to the uppercase quite well. I’ve used solvents and heat taking a few hours to get it off in the older 2016/17 models when I was able to get my hands on the part.
Frankly, the 16” part is about $150 USD getting a uppercase I think is the better direction today. First your battery is getting close to four years, your keycaps are likely a bit worn as well. A used uppercase can be had for $300 USD a new one from Apple is about a hundred more with a fresh battery.
But, I’m not sure you need a new TouchBar. Often the driver logic which is located on the cable is the problem.