I think it's instantaneous indexing, of at least the first page, if you have robots.txt set up correctly. You can test it to try to see how long it takes the first indexing (with the new titles if it's already indexed) by searching Google for: site:yoursite.com
However, the question is about Google Search Console reporting data. I find that it takes 48-96 hours before any reporting is updated for you to see after submitting the sitemap, etc., and it's very minimal as to what's shown. It takes about a week to two to get real useful data flowing in. But, if you have Analytics, you can get an idea of what you'll see almost immediately such as where traffic is coming from at a minimum, as Search Console lags behind it since Analytics reports in Real Time while Search Console has to aggregate keywords, pages, clicks, impressions, etc.
I only have 9 - 10 pages of indexed content on Google and I've been open for 6+ years. I had 30+ pages at one point, but that didn't last long. I don't have content consistently posted across my forum, so no wonder Google Bot is not finding more content to index. Also, I use non-self-hosted software so I don't have as much power behind the wheel to enhance my SEO.
I check my Google Search Console on average every other day. I've received 50 clicks in the past 3 months, which isn't terrible considering the minimal content indexed. I've had 1.93k impressions, however.
It has been almost 60 days since inception, and my google results are about 500 pages spidered with about half of them fully indexed. I am starting to see about a click thru a day now from the SERPS.
Since the topic of this thread directly related to my startup, I though another update was useful.
Just fyi, I have made no seo adjustments and only using the stock XF seo features.
Currently as reported by Google Search Console, 134 waiting to be indexed, a few other various reasons, but I have 317 indexed pages with 501 queued for index for a total of 818 pages.
I do note pages blocked by robots.txt etc that are expected.
So far so good with no declines in indexing. I know I still dont rank very well in the serps but that may take time.