Well... 'the world' uses Let's Encrypt, so I guess some parts of it work quite well
Personally I've never ever had any issue with renewing Let's Encrypt certificates on either Linux or Windows. For Linux (Ununtu LTS) we use a simple cron job, which has been running for about 6 years now without issues, even after server OS upgrades. It would certainly improve site security.
Same for mail. I am currently locked out of my main account here, as I changed that to a hotmail address, which seems to block mail from AradeControl at a rather low level. Looking into it, there is a practically useless SPF record, no DKIM, no DMARC and TLS1.0 and 1.1 being configured. Being an owner of an IT company, and having had to help several customers out of issues with mailflow not working correctly, I can't blame Microsoft for blocking those mails. In fact, if everyone blocked unsecure (email) connections, the internet would be a much safer place.
It doesn't take a lot of effort to take things up to a better level of security. If you need any help or suggestions, just ask!
-I- use letsencrypt and it took several renewal cycles worth of testing to ensure the damn thing would renew right. that's just me i guess.
but, for reals... let's put this into another perspective...
if absolutely NOTHING changed other than going from HTTP to HTTPS.... what would change? how would the security here be improved? it would not.
all HTTPS does is secure an encrypted connection from the arcadecontrols server... to you.
now, if you were transferring bank data, creditcards, or confidential weapons schematics... sure... but FFS, we are talking PUBLICLY about literal crap here most days. if ruskies want to see what data i'm sending... all they would have to do is wait till i submitted the post and READ IT. it's literal public info. and if i'm sending something by PM that requires any sort of security, i'd be doing it some other way, cause PM's are NOT for that kind of stuff anyway.
If chinashills want to edit my post on the way through to edit out "1989 Tiananmen square" to say "1989 nice day nothing happened" then by all means give'er bullets.
honestly, dismiss the HTTPS error message and you'll never see it again.