Now, my SSL connection with Cloudflare is Flexible, not Full Strict. Because, when I used Cloudflare's Full Strict mode, sometimes I couldn't access the site myself! But, Flexible Mode is somewhat risky.
That is why, I have considered a possibility to return to Let's Encrypt, which had been initially installed for me. However, online SSL test services say that my Cloudflare certificates are OK.
Can you provide more details of why you could not access the site with Full Strict enabled? What kind of URL were you using that didn't work (http://, https:// with alternate port, or ??)
With Full Strict, were you using a Cloudflare Origin CA Cert on your Origin server (at Asura)?
Have you discussed your concerns with Asura Hosting? What did they explain?
Personally, I'd suggesting working with your hosting company to use their free cert and recommended configuration. That's what you are paying for and they are nice enough to offer that.
And, even if it was just a cert problem you might be able to use Cloudflare's Origin CA Cert.
If you are not happy with proxying your domain at Cloudflare can't you just remove that? It looks like you have been using it for about a year. Before that you had a Let's Encrypt certificate. Just undo the Cloudflare proxy and go back to what you were doing then.