Should I steer clear of new miners because of this

Can erratic power damage your mining rigs? That's one reason I'm hesitant to dive into Bitcoin mining, even though my electricity costs are super low for it. A friend warned me that I might just end up wrecking all my gear. So I’ve been sticking with my old equipment, but now my S19 miner is actually not making me any profit. Still, I keep it running because I worry that the newer models require a more delicate power supply that could easily fry, unlike my S19 which feels tougher. Is it true that fluctuations from 180v to 220v could fry a modern Bitcoin miner?

It can kill your miner if you have an unstable power source. It can bring your PSU overheating due to an unstable power source. But I don't think you need to avoid those modern units. You better look for a way to solve your issue about power stability. If you don't have the knowledge to solve this issue, I recommend hiring an electrician. Let the electrician diagnose the issue, and if it's just a wiring issue, it can be solved easily, but if the power stability is caused by an external source, then there's nothing you can do. If S19 works for you, then keep using that, or else I think UPS can solve this, but it's expensive.

That means the S19 works fine even with unstable lighting? Or what you're trying to say is the machine doesn't take much current? So you're asking to know if a bigger mining machine can cope? The thing is you need to fix the electricity just as BitMaxz said cause you might not know how much damage it's slowly causing. A modern miner may take more current if the S19 alone takes about 200v-240v of electricity and trust me, it's not advisable to risk it.

Each power supply has technical specifications indicating the minimum and maximum voltage. To avoid writing similar posts, read this thread. https://bitcointalk.org/index.php?topic=5559666.msg65826627#msg65826627 You need a voltage stabilizer. It's much cheaper than a UPS.