Also an ESET user here who’s locked into it staying on for company reasons, and I do think there’s some conflict between ESET and Local’s generated certificates that’s causing issues, but I still haven’t been able to narrow it down any further. I tried deleting Local’s certs in certmgr, temporarily disabling ESET, then generating the new certs and it gave me different behavior but ultimately still did not resolve it completely. I recreated my dev environment on my personal machine and it didn’t experience the issues at all there, so I’m near-certain it’s ESET.
Independently (I think), if you check any website with a Let’s Encrypt cert (including sites hosted on Flywheel), ESET reports it as the parent of that cert, which has got to mean it’s scanning it and messing with it in some way, but I’m no ESET expert.