Google can't index my site - GSC returns "site-wide issue" - Bing and others index it fine, site scores really high in speed tests etc etc... Help?

Title, basically... Sometimes it actually puts it in line to index, but then takes a while... hours... most of the time it returns the error, though... Testing published URL works 25% of the times When it indexes it shows up in searches, news and Discover - I rank quite well depending on the relevancy of the post, no issues there... but usually I'd have it indexed in GSC in minutes, and then 1-2 hours for it to show up, sometimes less, sometimes a little more... now it's 6+ hours to index in GSC :( Started 5 days ago... What could be happening? Thanks in advance!