This eventual sluggishness is due to inevitable OS rot. I bought a brand new MBP in 2017 and it was snappy as hell. Booted up instantly, breezed through complex tasks, and ran GarageBand and Logic Pro X very smoothly. Every OS update seemed to take it down a notch and eventually Logic Pro X - my main production tool - was unusable. I happed to be talking about this to a professional music producer friend of mine and he said that everyone in his industry NEVER updates their OS. Basically they install everything, disconnect from the internet, and don’t touch the OS ever again because it can break delicate plugin ecosystems and drivers. That’s essentially what I ended up doing. I installed a different DAW (UA Luna) and have not updated the OS for about 5 years now and it’s still chugging along. I don’t use that system for any other purpose however I do keep it connected to the internet for ease of access to icloud. One day the hardware will die, but my next audio production system will likely be a Mac Studio that I set up and don’t touch for 10 years.