I've been using Windows 10 for some time and don't have a problem with it and wouldn't restrict my choices to only Windows 7. Most laptops are coming with large hard drives and any updates aren't a problem with storage space.
My current laptop is a Lenovo and I've had it about 5 years and haven't had any problems with it. I'm not sure that it makes that much of difference whether you purchase a Dell, Lenovo, or other brand as long as you have a warranty and can return it if there is a problem. Due to their return policy, I would consider purchasing from Costco, and they do offer some deals on Dell computers if you are leaning that way.
Personally, I've found ad blockers to be more of problem than they are worth and would rather just block popup screens when needed.
Are you talking about a tuner for musical instruments? If so, you can see what is available from the Windows Store and download a few freebies and see what works. I'm old fashioned and still prefer a small conventional tuner.
You may want to consider whether you want a glossy or matte finish screen AND how easy it is to see the laptop screen when sitting outdoors. I find it difficult to use my Lenovo laptop outside, as well as my Asus tablet. My wife's Kindle has a much brighter screen and works much better outside. It's something I may consider when I replace my Lenovo and I will most likely look for a screen with no glare.