I use a lot of Ikea's Tradfri stuff with my Home Assistant (plus ZigBee adaptor) setup. It's been pretty reliable for me. And it's all priced pretty reasonably.
I have an older comment somewhere about the setup, I'll update this comment when I get home and can find the link. It does take some additional hardware and some time to read up on it and set up Home Assistant. But it's open source and works with a huge range of hardware and doesn't require any apps (though a nice one is available on F-Droid). It runs entirely on a computer of your choice on a LAN. Not only do you not need an internet connection to use it, you don't even need one to set it up from scratch.
Any smart-home hardware that advertises itself as not needing a hub will need some corporate app and an internet connection. The "hub" still exists - it's just running on the manufacturer's servers.