Cut a corner too close when I was parking and scraped a curb. How big of a problem is this..? Safe to drive or not?

Cut a corner too close when I was parking and scraped a curb. How big of a problem is this..? Safe to drive or not?

That should be replaced and really soon - don't go on a freeway / motorway with it like that, as it looks deep. Even running around town it should be replaced asap...
Sidewall damage such as shown cannot be repaired. Furthermore, any sidewall damage, because of mechanical forces and the materials nature, is subject to catastrophic failure. This could be a blow out, while at highway speeds in heavy traffic, which creates an extreme risk.
To answer your questions: Big problem, not fixable, needs new tire. NOT safe.
Try this. Take a pressure gauge and monitor how much air is being lost every 4 hours. If it went flat down to less than 10 psi, replacement is necessary. If there is no air loss or minimal of 1 psi per 4 hours, there are bandaid patches available with instructions and glue plus a heater, use that.
Just remember, 'bandaid' is a temp fix. I will not be responsible if it doesn't hold anymore or if you hit another curb what the end result might account to.
You be the judge whether you want an aid or a full replacement.
Everyone will try to convince you to their logic, I'm showing you dealer level patch jobs (not always the safest).