No AdSense Impressions on a site newly converted to Drupal 8 - drupal-modules

Question

I am scratching my head trying to figure out (and yes, I know there are multiple reasons this could be happening) why my AdSense Impressions have dropped to 0 after changing my site to Drupal 8.6.4.
I have installed the Drupal AdSense module, into which I've put my "pub-XYZ~~" account number.
I left it like that for several days thinking perhaps the crawler hadn't found it. Then I got cold feet and thought perhaps it wasn't working, especially since I didn't see any AdSense code appearing in the source of the page.
So I added the following code via Asset Injector into the head of the page:
<script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"> </script>
<script>
(adsbygoogle = window.adsbygoogle || []).push({
google_ad_client: "ca-pub-239656292892567776",
enable_page_level_ads: true
});
</script>
(That's not my real client ID, just random numbers.)
Now I see a line of script in the head of the page:
<script src="/sites/default/files/js/js_Gc2nyd2PQaQJQwlbfhfc8Yz8TwWRl90UGM3vTenwS8s.js"></script>
And that (if I click on it) opens up the Google AdSense code I've written above.
Yet I've waited two or three days more, still not seeing any impressions, page visits, CTR (every metric on my "Performance" report is zero), and I am concerned that maybe I've done something wrong.
So does anyone know, if I'm using the Drupal AdSense module, where do I see the code?
And two, if I'm using the module, where can I see the code appearing in the source? (The Google answer doc says "You can do this by viewing the source of your site from a browser and double-checking that the ad code looks exactly like the code we provide you in your account, and includes every line of the ad code." But in the Drupal AdSense module, the only field is one for that pub-XYZ~~~ number, and nothing else, and as I mentioned, I'm not finding the code anywhere in the site when I view the source.
Three, if I'm using the module, will it mess things up to have the code above put in via the Asset Injector?
And lastly, am I just too worried and the AdSense module is doing what it should and I should check back in 10 days or 20, rather than in 5 or 7?
Thank you for any help. I had just installed AdSense (by adding it to the head of the page, this exact code) on the old site before switching to Drupal, and it was definitely working then, so I know that the issue isn't that the site isn't approved or the account's invalid or such. It WAS working fine. But after this move to Drupal 8, it's completely failed and I just don't know which link of the chain is the one I should fix. I have been scouring both Drupal docs and AdSense docs for this issue/answers and haven't found anything that seems to be the issue...and I really am hoping to know if the code side of it is correct.
Again, thank you in advance!

Answer 1

Okay, so for anyone else who needs this info, I'm answering my own question: I never did get the Google AdSense "auto ads" to work on my site, and am pretty sure the reason they didn't is that I was trying the "auto ads" code rather than the on-the-page, placed ads type code. I still don't know if it was simply a matter of time and the crawler hadn't found my site again, or if I had incorrect code, or what.
But I am now seeing an ad on my site, and what worked for me was:
Turn off any AdSense code in the head of the page. (I had injected the script via Asset Injector, and I disabled that.)
Make sure Drupal's AdSense module is running. DEselect the option that asks people if they wish to turn off their adblocker. The only thing I added in AdSense's main config window was my "pub-XYZ~" number.
Ditch the Google "auto ad" option and do the "Ad Units" option, creating an ad in AdSense. (AdSense > Ads > Ad Units). Do everything there and get your ad ID#.
Back to Drupal: Either create a new custom block or use one of the Drupal AdSense options to create a block on your site. If you use an Drupal AdSense option, it prompts you for the info needed to display the right ad. You'll need that ad ID# info at the very least.
Make sure that block is placed on your page. I chose "Responsive" but presumably this works for all the options. Fixed size, etc. I believe you could also (if you wanted) simply place the Google code directly into a custom block and use that. It seems people do.
If you've done it right, logged into your Drupal site, with the block placed, it will show placeholder text with your pub-# and ad ID#, in a little box. You won't see an actual ad (this is in the "Help and Information" option at the top of the AdSense module config). If you're seeing the placeholder box, it's a good sign that everything's going well with the Drupal AdSense module side of it.
Then wait, and wait, and eventually, logged out, on a private browser window, you should see the ad when the crawler finds it and other magic happens. I waited about 24 hours after setting this whole thing up before seeing an ad appear.
(Please note that this all was with a site that had a working AdSense account and had previously been getting lots of impressions for the ads. So if you don't have those aspects set up initially, none of the above will work either.)