Instant Indexing stopped working suddenly after a few weeks, reached api limits?

So a few weeks ago I’ve set it all up as per instructed, added the user at the google search console and pasted the JSON key content at the settings tap of the plugin.
Everything worked well – each new post was indexed by google almost instantly, like 10-15 seconds.

Yesterday it suddenly changed, posts took longer – 10-15 minutes instead of instantly index… I checked the plugin and it showed “success” status. At the limits area, I saw that they are maxed out and stuck this way.

I cannot apply for higher Quotas, because my use is neither job postings or livestreams (these are the only 2 option there, you must pick one).

I did try to get a new JSON key from a different google account, I added the new user in the search console and pasted the new JSON key, but the limits on the plugin did not change:

PublishRequestsPerDayPerProject = 145 / 200
RequestsPerMinutePerProject = 600 / 600
MetadataRequestsPerMinutePerProject = 180 / 180

So even a Quota increase wouldn’t help, because the issue is not with the per-day limits, but with the other 2 which got maxed out and are stuck at this status, even after I got a fresh new JSON key from another account (not the one that was used for the last weeks).

How can I get instant indexing back? How can I reset these 2 maxed out parameters? New JSON key from different account is not enough, would changing the Google search console owner for my site help (make it a new account as well), or is it that my domain itself is limited/blacklisted or something…

Edit: On new added posts, the plugin still gives back a success message when checking the status, the per minute limits start to decrease from the maximum (of 600, 180) but then again max out 180/180 and 600/600 – without publishing any new post. The limits of these 2 parameters just change – decrease and then max out again without any sense.