A VPN has it's advantages, mostly to avoid your ISP snooping on you (while having to trust another party not to snoop) and giving you access to stuff in the internet that may be geoblocked.
A solid DNS provider with Doh or DOT will encrypt your browsing, so I also believe it's better than a VPN, but I use both.
It's a matter of not overdoing it. Do it one step at a time. I feel you on the ADHD, I am also diagnosed, and now I inly check Lemmy and Mastodon every now and then. My mental health has improved dramatically since I dropped all the mainstream social networks.