Most onion sites are run by amateurs and are thus going down
temporarily/permanently all the time. This can be seemingly exacerbated by
indexes not removing links that have been down for a significant length of
time. If you can access "big" onion services such as Facebook's
(https://facebookcorewwwi.onion) or DuckDuckGo's
(http://3g2upl4pq6kufc4m.onion/), then you're very likely trying to access
onion services that are down. There's probably nothing wrong with your
configuration.

V3 onion services were flaky in January 2021. For why
https://matt.traudt.xyz/posts/tracking-tors-network-wide-v3-onion-service-outages/

An index of actually good onion services:
https://github.com/alecmuffett/real-world-onion-sites.  There's not really a
good search engine that indexes onion services. Maybe try http://ahmia.fi.

If you've never made a search engine before, please don't try to make one for
onion services. It won't be any better than anything that already exists.
Instead, maybe run a relay or fix a bug or host your blog as an onion service.
Get involved and be an advocate for Tor!  https://community.torproject.org
