Just to add my 2 cents. I only just started trying to use google_assistant and immediately found it to be very unreliable. I have been accessing my ha through duckdns with https for months but google_assistant just didn’t work well.
I spent the morning setting up cloudflared and it works amazing. Luckily I already had a domain for my personal website, I migrated the nameservers to cloudfare and was up and running. I know nothing about this stuff so if I can do it, anyone can!