I'm sorry this happened to you, but it highlights another very important factor. Don't keep all keys to the kingdom on one person. Always divide and conquer. Keep power distributed between multiple people. I worked at a company of 500+ people, and I'm sure the CEO didn't have access to all the IT people's stuff. They only cared that everything works and meet their quarterly goals. Shall the IT person feel like sabotaging stuff, there are distributed backups and mainly the fine print in the work contract preventing that.
I know this doesn't necessarily apply to smaller companies and startups, but have lawyers write you strong contracts that aren't one-sided, but are full of protections for both sides, if they aren't sabotaging stuff.
See, this is my problem when I start to think about stuff. I always take it from the most complicated angle. I didn't look at it as Bluetooth headphones that record stuff directly.
O2 (The Czech HQ'd PPF owned, not the UK one) - WISP
And even the more regional, but still big, aren't much better.
UPC (Liberty Global subsidiary) - Cable
Antik (Slovak company) - FTTx, Cable, WISP
SWAN (also Slovak company) - DSL, FTTx, WISP
But I have to shout out my dad's ISP, it's called RadioLAN, it's a slovak company, provides WISP and FTTx and also IPv6 to everyone by default. So far the only one I've found. Funny thing is, the peering in our country is handled by two IXs: SIX and NIX both natively supporting IPv6 interconection. If I've messed some terminology or I've outdated info, I'm sorry. As you said, nod to until we live in a very very specific location, we're left with just one ISP, or basically the same one in blue. I'm less than 10km behind the capital's outer borders, yet I have a huge problem getting FTTH ran here. It's literally connected at the both ends of our street, just not here. I've considered doing something about it myself, it's just simply too expensive.