I’m afraid the problem is not indexing, but monetization. Alternative google search will not be profitable (especially if you have to pay a share to google indexing) because no one will buy ads there - even for bing it is a challenge
If search providers could at least match Google quality 'by default' that might help break the stranglehold wherein people like the GP are at the mercy of the whims of a single org
How sure are you about that? I find them to be subpar when compared to Bing, especially for technical search topics (mostly, PHP, Go, and C related searches).