Trouble with environment variables in a Next.js project

can someone please help me with this:I do have a .env.local with the correct name and value for the env variable. I know this because I used those same values to get access to my content in my local site. So, why did this not work. Thank you in advance.
This is a nextjs project (if that helps at all)

When you start your local dev environment, does it say that it picks up the env.local file in your console?

Yes, it does. When I go to /studio locally everything works as expected. I ended up removing the assert function used in sanity.cli.ts file (or the other one in the root) and did sth like:
And that worked for now but I don't think that's a good idea. But for now, doing that helped.

I even printed out the env variables in the same file and it.printed correctly. Somehow that assert function call kept throwing Error. I couldn't solve it so had to go that route

Hmm are you trying to pick them up in your front end or in your studio? Seems like you’re inside a studio when I look at the url? I think env variables inside the studio requires a bit more work/setup: https://www.sanity.io/docs/environment-variables

I got that error after I ran

sanity build

and then

sanity deploy

and tried to visit the URL. After reading the docs, I think I used the NEXT_PUBLIC_ variables for both local studio and the version I was trying to deploy. The doc says it should start with SANITY_STUDIO_ . Thank you for your time. I will resolve it now.