Don't listen to anyone here, OP. You know in your heart of hearts that use cases be damned, you want an M5 Ultra with 512GB memory and 8TB SSD. Just lease it. Live like there's no tomorrow, baby! With that beast, you can sleep like a baby at night knowing there isn't a thing on planet Earth that you can't accomplish... yesterday, today, or tomorrow... you'll be all set. And no need to worry about re-sale value, just trade it in for an M8 Ultra when the lease is up. 😉
When I'm not running local LLMs or multiple VMs, my M5 Max MBP 64GB feels no different than my wife's M4 Air 16GB with most of the tasks you mention and day-to-day productivity. If your songs and videos and photo editing aren't particularly sophisticated you don't need 32GB. Ripping movies/CDs mainly depend on the speed of your drive (I have a Panasonic Blu-ray read/write and rips movies at 8X and audio CDs at 24X drive speeds on my MBP or wife's MBA - processor cores and memory make no difference). I haven't used an Excel or Word or PowerPoint large/complex enough (biggest files I work with ~50,000 rows / ~525 slides) to see a difference between my MBP and wife's Air. Loading large files quicker is really the only difference and that's mainly due to my MBP's SSD being roughly 4X faster than her Air (12,228MB/s read vs 2,858MB/s read).
As to future-proofing, upgraded wife's 2015 Intel MBP 2.8Ghz 4-core 16GB 1TB SSD macOS Monterey (could run Sequoia with OCLP) in January and only because she knocked it off the kitchen table and I didn't want to replace the screen again (2 screens, 3 batteries, 10 1/2 years). In all those years, it never got slower as far as macOS was concerned. She was even cranking out a bunch of AI-generated videos for fun last December and it would knock them out in a reasonable amount of time (she was floored at how much faster her new M4 Air was and wondered why she didn't upgrade sooner, and believe me, I had been trying to get her to accept an upgrade since M2 days). Anyhow, all this to say, Apple Silicon memory doesn't use magic or special unicorn DNA, but it is super efficient with memory. If a 2015 Intel MBP can still be capable of pretty much all your use cases after 10 years, I am very confident an M6 16GB 512GB mini will be good for 7-10 years. And if your needs change in say 2 or 3 years, you'll get decent trade in value and can buy the future model with the memory and storage you need, when you finally need it.
Or... succumb to the FOMO/YOLO tug of the universe like I did and buy something wildly more powerful than you currently need. 🙂
