Hi there,
normally it shouldn't affect performance that much but I have seen batteries with that msg to cause a few issues including system slowdown. It shouldn't be a Logic Pro X only issue. (Plus you're on Mojave which already slows down performance a lot on a 2014 machine).
What is the cycle count of your battery? You can find it at >about this Mac> System Report (below serial no) > (Hardware) Power. (you can also option click on and select > System information).
You could reset SMC (Reset the SMC on other computers), check also Maximizing Battery Life and Lifespan.
Not sure if an apple store is close, if they're open for repairs etc. Apple recommends replacement with "Service battery" meaning that the battery doesn't behave as expected and needs replacement, it might expand etc.
Contact Support or here's the International Contact No's or download the Apple Support app if available in your country and you'll find more info about booking a repair/diagnostics etc.
iFix it has an economic option if you're good with repairs and not planning to repair your 2014 MacBookP at an apple store in the future.
A quick search in the forum and you'll find many posts on "Service Battery".
A