I've been looking into mini PCs for years and I've kinda given up on the idea.

Mini PCs usually use the same low power CPUs you find in laptops, and if they don't, you pay a serious premium over both laptops and regular desktops.

Laptops used to be several generations behind desktops, but that's dramatically changed in the last 5 years.
You can get a 12500H laptop with 16GB of RAM and a 1TB M.2 drive for 800-900€ and have 5600X levels of performance in your lap.
And that's not an eye watering amount of premium to pay over buying a desktop with similar specs.

 

heavy graphic config are hungry in electrecity and mostly useless for audio

 

You can always go into power options and force the laptop to use power-saving integrated graphics to save on power as well as disabling boost, its what i do with my zephyrus g15 4900hs/2060 based laptop and it stays at 60c during even very large projects and the performance is only marginally worse at this config than my ryzen 5 3600 but is 10C cooler.

 

If I was you, I would probably just go and get a Mac Mini or an used Macbook Pro. As much as i hate Apple, this new machines are just unbelievable good and you can get really good results with the base cpu model, because all of them have the same single core performance. Actually, I have a Ryzen 2700 PC that I use just for audio and probably this year I will make the switch. The only problem is that I live in a third world country, and Apple prices here are retarded, to say the least.

 

Always more power.
We made music with Pentiums and then with core 2 duos.
I have a 4 core I7 laptop with a samsung NVMe and a crucial 1Tb ssd, 16 gigs of ram without graphics card. Bought 700 euros four years ago.
I record bands in the summer with this laptop.
I use it with kontakt and synths and plugins. I don't freeze that much. Especially with Reaper.
Of course I have an overclocked I9 9900 K and 64 gigs of ram. And I think I'll keep it until the first atomic bombs fall on my country.
So if this person wants to make music with this laptop, he can. Ciao!
Let's come back to earth.

 

for 700 that's a decent pick,
only fair comparison is MacBook Pro 16" 2019 (2.6GHz i7) which uses exact same cpu, and sells for around 1000 bucks,
base model M1 Pro MacBook Pro 14 sets you over 2300$ I can only laugh at its costs, not even funny to consider seriously,

either way you're investing money into 4 years old laptop, price drop may be worth it as long as you can live with risk of failure, not covered by warranty service,
me - I'd rather buy used desktop just because I could upgrade individual components overtime

 

Thank you very much for your answer. I think I'll save some money and build a PC following your advice