Well, you're going to run into issues with macOS support in short order (already for PPC). And macOS is mostly the point of running a mac.
Where this will start to show is things like:
- digital certificate support
- TLS version support
- codec support
- things like passkey support
The performance is what it is, but those things will interfere with your ability to use the internet - if not now, as time passes and software support is dropped from the platform.
The first two factors are what will truly kill a device for modern internet use - there's a big push for encryption on every website and when your device no longer supports the encryption used - the web just won't work any more for you.
Sure you could then install Linux on the thing and if you're willing to do that - that's fine. But if you're going to end up on linux, you can get a more performant, modern machine for less money when macOS is not a constraint... so I'd advise doing that - if you plan to be using the internet with this device.
old hardware/macOS to run old software offline - go nuts. internet will be painful sooner rather than later.
Tahoe is end of the line for intel, and OLCP is not going to remedy that due to the drop of intel support in macOS.
edit:
to be clear: i'm not saying "DON'T DO IT!!". do what you want - just keep the above in mind if you're expecting to use it on the internet moving forward.
I myself have a trashcan on my desk because i like the aesthetics and i think its destined to become an art piece. Its still mostly usable on the internet with the officially supported OS; i tried OLCP to run more recent platforms... with mixed results.