My experience was: get 3-year certificate for free, install it and forget about it. With LetsEncrypt, it's always pain, expired websites everywhere. Too bad that american IT mafia put these good CA out of business.
American IT Mafia? That provides free certificates? You'd think setting up renewal would be less of a hassle than dealing and paying CAs even if it's once every 3 years, so that would be a rather benevolent mafia. Which of those CAs went out of business by the way?
Do you think Let's encrypt is less popular outside the US?
I was about to say that I never encounter TLS errors while browsing, but that's not strictly true. There is one such website, and it's only because the webmaster had a stroke and can't maintain it currently. But apart from that rather sad story I can't relate to your issues at all.