What exactly have you tried to do to address your nextCloud problems?
BloodyIron
How exactly can they tell I'm even looking at it without clicking anything at all? Like I know websites have that ability, but to what extent does eBay pass that info to sellers?
I've been self-hosting my own websites for over a decade, and while the hug-death of the "slashdot effect" can be real, it is a statistical anomoly and a absurd as a rationale against self-hosting. It is actually cheaper ($ wise) to self-host with equipment you already have. Certs are $0 with LE, everything else is just setting up systems (websites) on equipment you already run and pay for. It is a lie to say that that's somehow more expensive than $14/mo.
If someone chooses to pay for hosting elsewhere, that's one thing, but don't sell the lie that it's cheaper. It's not.
As for the 100k/day unique traffic, that depends on the website served. If it's a fully static site and your setup is tuned, yeah you can actually handle that.
I bought a Samsung Galaxy S4 from my GF like 6 years ago for $50. She of course upgraded her phone. I replaced the OS with LineageOS and slammed the ability to boot from ISOs over USB onto it. I now use it as a backup way to boot from ISOs over microUSB->USB-A in many different forms. It's not as fast as I can get with better USB thumb drives, but in a pinch, it's there for me! I know this isn't exactly me writing code here, but I had to unlock the boot loader, replace the OS, root it, make sure Google Play worked on it (that was a touch of hacking, but again not my code), and stuff like that. So it's a legit device as far as Google Play can tell and all that! Also the S4 has a removable battery so yay!
Yes this is self hosted related because I use these ISOs for server stuff, be it Proxmox VE OS install, OPNSense, or even firmware bootable ISOs (although those I probably should have on a dedicated thumb drive that doesn't require a battery to live lol).